WASHINGTON (AP) -- The Internal Revenue Service says late changes to federal tax laws should mean only a short delay for most taxpayers to file their 2012 returns.

The agency said Tuesday that more than 120 million taxpayers -- about 80 percent of all filers -- should be able to start filing their federal returns on Jan. 30. Others will have to wait until late February or March to file because the agency needs time to update and test its systems.

Those who will have to wait include people claiming residential energy credits, depreciation of property or general business credits.

The filing season had been slated to start Jan. 22 but was delayed because of the big tax package passed by Congress Jan. 1.