WASHINGTON – A crucial band of Senate Republicans and Democrats is pushing for tax cuts less than half the size President Bush seeks to stimulate the economy, the most concrete sign yet that the White House will not get all it wants for its cornerstone domestic initiative.

About a dozen centrist Democrats and Republicans – who hold the balance of power in the narrowly divided Senate – have met for weeks to craft an alternative to Bush’s economic growth plan, which would cut taxes by $725 billion over the next decade. Worried that Bush’s plan would prove too big a drain on federal revenues, the centrists are expected to propose a tax cut in the range of $350 billion.

“It seems to be a number that is comfortable,” said Sen. George Voinovich, R-Ohio.

Both plans would cover a 10-year period.

The centrist proposal will send a strong signal to the White House that, despite weeks of lobbying by Bush and his allies to build support for his economic plan, the appetite among some lawmakers for tax cuts is spoiled by growing concern about ballooning budget deficits and the potential costs of war with Iraq.

Some Republicans say their concern about the deficit and war costs has grown so much that they now think Congress should wait until after any military conflict with Iraq before deciding the size and shape of a tax cut.

“I’m increasingly thinking the right decision may be to not support any plan until the fiscal situation is clearer,” said Sen. Susan Collins, R-Maine. She said she was worried that a $350 billion tax cut now could be the worst of both worlds – too small to jolt the economy, but still a big drain on federal revenues.

Some centrists – such as Sens. Lincoln Chafee, R-R.I., James Jeffords, a Vermont independent, and Tom Carper, D-Del. – oppose any new tax cuts.

But most moderate Republicans say they still support some cuts to stimulate the economy, just not as much as Bush has proposed. “We need to do something,” said Sen. Olympia Snowe, R-Maine, a leader of the bipartisan centrist group.

“But we have to have a sense of proportion about what we can do.”