Budget cuts recently passed by Congress could delay tax refunds in 2015, and the IRS is even considering a brief shutdown to save money, IRS Commissioner John Koskinen said on Thursday. 

Fewer agents will be auditing returns, said Koskinen at a news conference, and half the people who call the IRS for assistance won't make it through to a person, The Associated Press reported.

"Everybody's return will get processed," Koskinen told reporters. "But people have gotten very used to being able to file their return and quickly getting a refund. This year we may not have the resources, the people to provide refunds as quickly as we have in the past."

Under normal circumstances, if filed electronically, the IRS can usually issue most tax refunds within 21 days, but Koskinen wouldn't speculate on how long returns could be delayed in the upcoming season.

The newest spending bill passed by Congress cut the $10.9 billion IRS budget by $346 million for the next year - $1.2 billion less than the agency received in 2010, reported AP.

This comes when, for the first time, taxpayers are required to report on their tax returns as to whether they have health insurance. Millions who are receiving Obamacare tax credits to help pay insurance premiums will also have to report, leaving the IRS especially overwhelmed, and even considering a shutdown to save money.

"People call it furloughs; I view it as: Are we going to have to shut the place down? And at this point, that will be the last thing we do," Koskinen told reporters. [...] "but there is no way we can say right now that that wont happen."

"Again, I would stress that would be the last option," and would mean the agency would "close for a day, two days, whatever days it would take to close the gap that we can't otherwise close in a reasonable way," he said, estimating that each day closed could save $29 million.