Closing one of the train tunnels into Manhattan from New Jersey could cost the economy about $100 million a day, Tom Wright, Regional Plan Association executive director, said Thursday.

According to reports, some train lines would need to be halted to make repairs on the 105-year-old tunnels. The hit to the economy would specifically come from the loss of New Jersey Transit's Northeast Corridor line which brings thousands of commuters to New York City each day.

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"That would be a 75 percent reduction in capacity under the river," Wright told CNBC's "Power Lunch."

Each weekday the Hudson River rail tunnels carry more than 170,000 passengers in and out of Manhattan, according to the Regional Plan Association.

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Wright expects that if one of the tunnels were closed for renovations, Amtrak service could go to one train an hour while NJ Transit would see weekend service all week long.

Building a new tunnel is unlikely, he said, since it will need a $15 billion funding package and at least 10 years to complete.