U.S. Treasury Secretary Jacob J. Lew called a potential agreement to revive and extend lapsed tax breaks “fiscally irresponsible,” casting uncertainty over year-end negotiations in Congress.

Lew was responding yesterday to talks between Republicans and Democrats that would make permanent a few of the tax breaks that expired at the end of 2013 and continue others through 2015. Lawmakers are discussing a package that could increase the U.S. budget deficit by more than $400 billion over a decade.

Lawmakers have been trying to reach a deal that would include some permanent extensions of breaks for businesses, such as the research tax credit, along with some for individuals, such as expansions of the child tax credit and earned income tax credit backed by the Obama administration.

The precise contours of a deal haven’t been set, and staff members from both parties are negotiating the deal. Companies including General Electric Co. and Intel Corp. have business breaks at stake in the talks.

“An extender package that makes permanent expiring business provisions without addressing tax credits for working families is the wrong approach, at the expense of middle-class families,” Lew said in a statement. “Any deal on tax extenders must ensure that the economic benefits are broadly shared.”

A collapse of the bipartisan talks may send both parties to their fallback positions, with House Republicans urging an extension only through 2014 and Senate Democrats seeking an extension through 2015.

‘Good Faith’

“All parties are coming to the discussions in good faith,” Representative Dave Camp, chairman of the House Ways and Means Committee, said in a telephone interview yesterday. “It remains to be seen whether something will come together, but I think it’s worth a try.”

Just like they did after the 2010 and 2012 elections, lawmakers are working to piece together a deal on the collection of lapsed breaks known in Capitol Hill parlance as extenders.

The provisions -- including incentives to donate food and hire workers from disadvantaged groups -- have routinely been extended as a group, surviving attacks on individual items.