Internal Revenue Service officials accidentally handed out $27 million in refunds in 2013 thanks to a "programming error."

A pattern of "ineffective monitoring," identified by the IRS' watchdog, caused the IRS to hand out an additional $19 million before the agency verified that the recipients had provided accurate income information.

"We forecast that over five years the IRS could issue $135 million in potentially erroneous refunds due to this programming error," wrote the Treasury Inspector General for Tax Administration, which oversees the IRS, in a report made public Monday.

What's more, the watchdog predicted the tax agency "could issue more than $95 million in potentially erroneous refunds" over the next five years "because tax returns are not being verified as required."

The IRS "erroneously issued" refunds for 13,043 tax returns in 2013 thanks to the computer glitch.

Rep. Diane Black, a member of the House Ways and Means Committee, blasted the IRS for losing $46 million to the programming error and the lack of income verification.

"We didn't need another reminder that the IRS is mired in incompetence and mismanagement, but we got it anyway," Black said in a statement Monday.

"It is abundantly clear that Commissioner John Koskinen has failed in his duty to restore trust at the IRS and must be replaced, but Congress is not guiltless either," the Tennessee Republican added. "Just last week, my colleagues voted over my objections to give this bureaucracy another $290 million in the bloated omnibus bill."

"Only in Washington is this kind of ineptitude rewarded with a bigger check," Black said. "Taxpayers have every right to be outraged by the dysfunction at the IRS — I know I am."