Raleigh, N.C. — Changes to federal tax laws included in the deal Congress approved last week to avoid the so-called "fiscal cliff" mean the Internal Revenue Service won't start accepting individual tax returns until Jan. 30, officials said Wednesday.

The IRS said it needs the next three weeks to update programming and test its computers to handle most of the changes in the American Taxpayer Relief Act. Some forms, including those for residential energy credits, depreciation of property or general business credits, will require more extensive programming and testing, so anyone including those forms in their returns won't be able to file until late February or March, officials said.

“We have worked hard to open tax season as soon as possible,” IRS Acting Commissioner Steven Miller said in a statement. “This date ensures we have the time we need to update and test our processing systems.”

The agency had planned to start processing tax returns on Jan. 22, officials said.

The IRS plans to work closely with the tax software industry and tax professionals to minimize delays and ensure as smooth a tax season as possible under the circumstances, officials said.