A new Government Accountability Office report is reigniting the interest of Senate Finance Chairman Max Baucus in closing the “tax gap” between taxes owed and taxes paid.

The report, based on a September 2007 forum of public and private tax professionals, lists a range of ways to get individuals and businesses to pay more of what they already owe.

For instance, the report suggests, the government could increase its number of audits, focus audits on large entities, improve the quality of audits, increase required information reporting and share information with state tax departments.

Lawmakers have already been pursuing some of these ideas, particularly increased information reporting and tougher penalties.

Baucus, D-Mont., took the report as a sign that efforts to close the tax gap should continue.

“Most importantly, this is about fairness — this doesn’t raise anyone’s taxes,” Baucus said in a statement Wednesday. “The sooner we get full tax compliance, the sooner we can lower the tax burden for honest Americans who abide by our tax laws.”

Previous studies have indicated the gross tax gap for 2001 at $345 billion, meaning that the government collected far less than it was owed. The net tax gap — after late payments of taxes were subtracted — was $290 billion. That is the most recent year for which data is available.

The gap is attractive to lawmakers, who see closing it as a way to collect more revenue without raising taxes.

But succeeding is difficult. The tax system requires individuals and businesses to report their income voluntarily, and finding those who underreport or fail to file can be tough.

The report said: “The tax gap has been a persistent problem in spite of efforts to reduce it, as the estimated rate at which taxpayers voluntarily comply with our tax laws has changed little over the past three decades.”