"He who wants to import will be able to do so, and he who wants to buy dollars will be able to buy them," Finance Minister Alfonso Prat-Gay said.
Farmers in Argentina, a grains-exporting powerhouse, have been waiting for the peso to weaken before selling stockpiles of soybeans. Manufacturers have argued for controls to be lifted so they can import crucial parts for production.
Local and foreign investors, meanwhile, might be inspired to bring money back to the country if Macri's reforms succeed in reducing imbalances in the economy in the long-run.
Asked what he expected the exchange rate to be when markets open, Prat-Gay said there was "no magic number."
However, the most realistic level at the moment was the blue-chip swap rate, used to buy Argentine assets traded abroad. That rate is currently around 14.2 pesos per dollar, compared with the official exchange rate of 9.8275, implying a devaluation of around 30 percent.
"Let's see what happens tomorrow. The policy will be what economists call a 'dirty float'," Prat-Gay said. "There will be fluctuations in the exchange rate but there will also be a central bank with the necessary tools to buy if the currency weakens too much or sell if it strengthens too much."
Jorge Mariscal, chief investment officer for emerging markets at UBS Wealth Management in New York, said it was positive to see the new government immediately tackling the currency issue.
"The exchange rate was very important because it will eliminate all the distortions that were in the market," he said.
Mariscal said there was a chance the peso could weaken more than 30 percent at the start, "but there is also a significant chance that it comes back rather quickly."
"There is a lot of Argentine money outside waiting to come back once the new team builds some credibility," he said.
A Reuters poll of analysts released earlier this month predicted Macri's policies would spell stronger growth in the medium term after causing short-term pain. The devaluation is seen fueling inflation that private economists already estimate around 25 percent and thereby hurting private consumption.
The median forecast was for 3.5 percent growth in 2017 after a 0.5 percent contraction in 2016.