Sen. Arlen Specter, a Pennsylvania Republican, had already delayed introducing the bill last month because of objections from Democrats to the proposed text. On Monday, he announced a new delay while Republican considerations were addressed.

Specter did not detail the concerns of Frist, a Tennessee Republican, or members of the Senate Judiciary Committee who joined in the request for a postponment.

"I had intended to submit this legislation late last week, but I was asked by the Majority Leader (Frist) to defer for a week, so further consideration could be given by the majority leader and members of the Judiciary Committee," Specter told the Senate.

"It would be my request to my colleagues that the matter be examined and studied. We are going to have to move forward on it one way of another if the matter is to be taken up at an early date," said Specter, chairman of the Judiciary Committee.

Specter has said he would like the bill to come before the Senate as early as next month. The proposal was the "last best chance" to deal with the issue, he warned on Monday.

Frist' spokeswoman said he was working with Specter and the committee, but declined further comment.

Texas Republican Sen. John Cornyn, who Specter named as one of the Judiciary Committee members asking for a delay, said through a spokesman the proposal was complicated, with "major implications on those who are sick and need help now, our economy and the future state of litigation." But he did not offer specifics of his concerns.

Asbestos, a fire-retardant mineral, was once widely used for insulation and construction. Scientists say inhaled fibers are linked to cancer and other diseases. Thousands of injury claims are clogging U.S. courts and bankrupting companies.

Specter has been working for months on a proposal to take asbestos claims out of court and compensate then using a $140 billion fund instead. He is seeking to make it as bipartisan as possible in hopes of boosting its chances of passage.

Recently some Republicans have expressed frustration with the effort, saying Democrats keep demanding changes every time agreement seems close. Last month, Specter delayed introduction at Democrats' request while examining the bill's impact on other lung-scarring minerals such as silica.

Last week, Sen. Orrin Hatch, a Utah Republican and the committee's former chairman, said the proposal as it stood did not have much support from Republicans.

Aides say Republican senators worry the medical criteria for qualifying for compensation from the fund are too weak, and that a medical screening program in the proposal will drum up claimants who are not really impaired by asbestos. They are also concerned the bill would allow "double dipping" by claimants from the fund and from insurance companies.