New York hospitals and the state’s largest health care workers’ union are poised to launch a television advertising campaign in an effort to swing public opinion against Governor Spitzer’s plan to slow down the growth of Medicaid by hundreds of millions of dollars, according to a state lawmaker.

Assemblyman Richard Gottfried, a Democrat who is chairman of the chamber’s committee on health, said yesterday he spoke with an official at the Greater New York Hospital Association who said the hospital group and the union, 1199 SEIU, have given the green light to an ad campaign that could begin airing as early as today.

The ads would likely be combined with a lobbying effort to pressure lawmakers to restore the cuts in their final budget due on April 1. One source said the effort could include mailings to senators and Assembly members asking them to pledge to oppose Mr. Spitzer’s $47.5 billion Medicaid plan.

The groups, which joined forces during the Pataki administration to ward off cuts to the program, have on hand tens of millions of dollars in a joint fund called the Health Care Education Project, which bankrolled last year’s campaign against Governor Pataki’s budget.

The association and the union have kept their plans secret as they developed a battle strategy tailored toward a Democratic governor whose popularity with voters — one poll released yesterday found that 74% of New York voters have a favorable opinion of Mr. Spitzer — and willingness to strike back at critics makes him a trickier target than his Republican predecessor.

Last year, faced with an ad campaign that accused him of putting the lives of babies at risk, Mr. Pataki, who was recovering from an illness, tried to keep a low profile and ended up yielding to virtually all of the groups’ demands.

The biggest challenge for the groups could be selling voters on the idea that Mr. Spitzer’s budget is an attack on health care.

Unlike Mr. Pataki, Mr. Spitzer is not attempting to reduce eligibility for coverage or benefits. He’s proposing to expand the Child Health Plus program to close the coverage gap, extending access to 400,000 uninsured children in the state. And he’s increasing the total Medicaid budget by more than $1 billion versus the current fiscal year. Even the president of the Greater New York Hospital Association, Kenneth Raske, acknowledged in testimony last week before a legislative finance panel that Mr. Spitzer’s budget contained “very positive elements.”

The hospitals and 1199 SEIU are expected to argue in their ad campaign that hospitals, already in downward spiral, cannot survive the twin blow of Mr. Spitzer’s savings measures and President Bush’s recently announced proposal to reduce Medicaid payments to hospitals.

The hospital association estimates that New York hospitals will suffer a $475 million loss under Mr. Spitzer’s budget, which would equal 1% of operating revenue.

“When your starting position is negative, an additional 1% loss cannot be absorbed without affecting patient care. If even a portion of the proposed federal budget cuts are added, the game would, in fact, be over for New York hospitals,” Mr. Raske said in his testimony.

The biggest cut is a freeze to the annual inflation adjustment of reimbursement rates that help hospitals pay for rising costs. New York hospitals would lose $172 million on fee-for-service reimbursements.

Mr. Raske said hospitals and nursing homes would lose a total of $1 billion in upcoming fiscal year.