The Obamacare tax man cometh: Will you be ready?

H&R Block CEO: Maximizing refunds
H&R Block CEO: Maximizing refunds   

These Obamacare tax "tools" can't arrive soon enough.

The Obama administration said Thursday that in coming weeks it will release online tools and other resources to help people deal with the new tax-filing implications of Obamacare.

While more than 75 percent of filers are expected to have no problem complying with a new disclosure requirement, millions of others could face a time-consuming, complicated process to determine if they owe the government money or are owed money in connection with subsidies they received to help pay for their Obamacare health insurance plans.

Read MoreHow health insurance 'squeezes' workers

If peoples' annual incomes were higher than they first estimated when they applied for those subsidies, they will owe money back to the government. The reverse is true if their incomes were lower than estimated. About 85 percent of the 6.7 million paying Obamacare customers as of October were receiving subsidies, and research suggests that many of them could have had income swings during the year.

Millions of other people will be trying to figure out during tax season if they qualify for one or more of a slew of exemptions from the Obamacare mandate that they have health insurance during 2014 or face a fine.

Outreach efforts

In addition to the online tax tools plans the Obama administration plans to offer, the Health and Human Services Department also said it will "employ a variety of outreach strategies" and education efforts to help tax filers. Those include directly contacting, via email, phone and text messages, people who bought health plans on government-run Obamacare exchanges, and offering them "personalized information that is most relevant to their tax status."

HHS also said it will work with community groups, nonprofits and health insurance navigators to help consumers answer their questions, and will continue working with leading tax preparation firms to relay information to their customers.

Read MoreHealthCare.gov sign-ups approach 6.6 million

Treasury Secretary Jack Lew said, "For the vast majority of Americans, tax filing under the Affordable Care Act will be as simple as checking a box to show they had health coverage all year."

"A fraction of taxpayers will take different steps, like claiming an exemption if they could not afford insurance or ensuring they received the correct amount of financial assistance," Lew said.

"A smaller fraction of taxpayers will pay a fee if they made a choice to not obtain coverage they could afford. We are working to ensure that whatever their experience, consumers can easily access clear information since this is the first year they will see certain changes to their tax returns," Lew said.

While Lew's statement was short and simple, the IRS's own document detailing the "Health Care Law: What's New for Individuals and Families" runs to 21 pages.

And it contains sentences like this: "Taxpayers who receive a Form 1095-A, Health Insurance Marketplace Statement, from the Marketplace showing changes in monthly amounts must do a monthly calculation to determine their premium tax credit in Section 2 of Form 8962, Premium Tax Credit."

The administration on Thursday pointed to several resources already available online to help, including the IRS' Affordable Care Act page and Healthcare.gov's tax page. Several other resource sites include Health Care Law: What's New for Individuals & Families, 3 Tips About Marketplace Coverage and Your Taxes and No Health Coverage? What That Means for Your Taxes.

Will it be enough?

Health policy consultant Robert Laszewski, when asked about the administration's announcement of new tools and outreach efforts, said, "This is generally all good, but it is not clear if this will be enough with about 5 million people needing to be part of filing the new form" to detail their Obamacare subsidy payments.

This coming tax season is the first one in which filers will be required to disclose to the IRS in their tax return whether they had health-care coverage throughout the year.

The ACA mandates that, starting in 2014, nearly all Americans have some form of health coverage or pay a tax penalty equal to as much as much as one percent of their adjusted gross income.

But there are exemptions from that mandate.

H&R Block CEO: Maximizing refunds
H&R Block CEO: Maximizing refunds   

Intuit, which sells the TurboTax tax preparation software, noted that an estimated 20 million people may qualify for an exemption from the fine. An online TurboTax "exemption check" tool launched in October walks people through a series of questions designed to determine if they are eligible for such a waiver.

The questions include whether a person is a member of a Native American tribe, filed for bankruptcy, been a victim of domestic violence, faced their utilities' being shut off or had medical expenses they couldn't pay in the prior 24 months. All of those and others can lead to an exemption from the Obamacare mandate.

"We do everything on our end to make this as simple a process as possible," said Debra Hammer, an Intuit spokeswoman.

Calculating Penalties

People who don't qualify for an exemption and who failed to have insurance will have to fill out an IRS form to calculate how much money they owe government as a penalty. The Tax Policy Center last month updated its online ACA Penalty Tax Calculator, which gives filers a sense of what they may owe this year, as well as future years if they fail to get health insurance.

A potentially trickier tax filing situation will be faced by people who received subsidies to help pay for their monthly premiums for insurance plans sold on HealthCare.gov, the federally run exchange that serves 37 states, and the state-run exchanges.

The amount of the subsidies, which are tax credits, is contingent on a person's income. As a rule, the lower a person's annual income, the higher the subsidy they receive, and vice versa. Because most Obamacare customers applied for such subsidies eight or more months ago, there is a chance their actual annual incomes are different than what they had first estimated, because of raises, job changes, hour changes and other factors.

All customers who received subsidies must fill out a new IRS form detailing their incomes and the subsidies they received.

A study published in the journal Health Affairs in September 2013 analyzed the likelihood that Obamacare subsidy recipients would either have to repay some of their subsidies or be entitled to a bigger tax credit than they had received during the year because of changes in income if they failed to report their income changes promptly.

Pitfalls of income changes

The analysis, which used California as a case study, "found that many families could owe large repayments to the Internal Revenue Service at their next tax filing."

Read MoreObamacare effect: Uninsured rate hits record low

"We found that family income fluctuated greatly from one year to the next," the authors of the Health Affairs article wrote.

The authors said that more than 73 percent of people predicted to receive subsidies were in families that had income changes of more than 10 percent between the two years looked at, with a nearly even split between the number that had large income increases and the number that had large income decreases.

And "30 percent of the recipients were in families whose incomes increased more than 20 percent," and nearly 19 percent of the recipients had income increases of more than 40 percent, the study found.

On Wednesday, the CEO of the tax preparation firm H&R Block told the Reuters news service that the company expects about one in every four of its tax return customers to file either a form calculating their penalty for failing to have insurance or the form detailing the subsidies they received for their plans.

CEO Bill Cobb would not estimate the boost to H&R Block revenue this year from charging for the forms, but he did say that an outside analyst was correct in estimating that the charges could be between $5 and $30 per form.

Hammer, the Inuit spokeswoman, told CNBC that if people "use the right tools" the process for making Obamacare-related tax filings "can be quite simple." She noted that the relevant ACA forms are included in TurboTax products at no additional cost.