The Congressional Budget Office released a new estimate showing the GOP tax law will add $1.9 trillion to the federal debt over the next 10 years.

GOP Sen. Bob Corker, who ultimately voted for the final package despite concerns about the deficit and debt, was not happy to hear this.

"If it ends up costing what has been laid out here, it could well be one of the worst votes I’ve made," Corker said.

GOP Sen. Bob Corker is having second thoughts about his vote on the new tax reform law, now that there's a clearer price tag for the bill.

During a Senate Budget Committee hearing with the Congressional Budget Office, Corker bemoaned the large amount of new federal debt that is projected to pile up due to the new law.

"If it ends up costing what has been laid out here, it could well be one of the worst votes I’ve made," Corker said.

The CBO projected on Tuesday that the law alone will tally $1.9 trillion in new debt over the next 10 years. That was up from the Joint Committee on Taxation's estimate in December that the bill would cost $1.1 trillion over the decade. The increased debt levels were due to an adjustment in the CBO's formula for economic growth and the increased cost of servicing the new debt.

Corker originally voted against the tax bill in the Senate and was the only Republican to do so. The Tennessee Republican eventually flipped to a "yes" on the final House-Senate compromise bill.

In addition to bemoaning the tax bill, Corker also slammed the massive omnibus funding bill that passed Congress in March.

"This Congress and this administration likely will go down as one of the most fiscally irresponsible administrations and Congresses that we’ve had," Corker said at the hearing.

A new estimate from the CBO also showed that the US will hit an annual budget deficit of more than $1 trillion starting in 2019.