A new Massachusetts sales tax on software and computer services has been met with anger and confusion among technology firms.

Business leaders brand the measure an "innovation tax" that could damage the state's economic recovery. They say the tax is so vague it's difficult to be sure who should pay it.

Two groups, the Massachusetts Taxpayers Foundation and the Massachusetts High Technology Council, are calling on lawmakers to repeal the tax when they return from summer recess. If the Legislature doesn't act, opponents say they'll take their case directly to voters.

Sen. Stephen Brewer of the Senate Ways and Means Committee says no decision has been made on whether to revisit the tax. But he notes it was part of a transportation financing plan that business leaders said was needed.