PORTLAND, Maine — Republican Sen. Susan Collins is letting the GOP’s Senate leadership off the hook on her promise to shore up health care premiums by year’s end in return for supporting the tax overhaul. But she said she will resume the push in the new year.

Collins and fellow Republican Sen. Lamar Alexander, of Tennessee, the chairman of the Senate Health Committee, announced Wednesday that they’ve decided to wait until early in the new year to press for health subsidies for the poor to soften the repeal of the individual mandate.

They said it has become clear that Congress has run out of time and will pass only a short-term agreement this week to avoid a government shutdown.

Collins said House Speaker Paul Ryan told her that the House remains committed to high-risk pools and other reinsurance mechanisms similar to the bipartisan legislation she’s introduced. He said that by waiting until January more funding will be available based on new Congressional Budget Office data.

The proposal, which was a demand by Collins to support the GOP tax bill, is aimed at stabilizing health insurance markets after the repeal of the mandate that individuals purchase insurance.

Collins voted for the sweeping tax overhaul after her amendments on property tax and medical expense deductions were included. She also says she secured a promise from House and Senate leaders to remove the threat of a 4 percent cut to Medicare.