By David Lawder

WASHINGTON (Reuters) - Rep. Barney Frank said on Sunday he will put together an economic stimulus bill when Congress returns to Washington after the November elections, while a key Republican said he would support the effort.

Frank, chairman of the House of Representatives Financial Services Committee, said on ABC television that he would begin work on the stimulus bill in November in a "lame duck" session.

Rep. Roy Blunt, the Missouri Republican who serves as House minority leader, said he would support a stimulus plan if it did not include a massive public works program and budget bailouts for states that overspent on health care and other social programs.

"A stimulus plan that makes sense is something that I'll be helpful with," Blunt said, also on ABC television.

The two lawmakers also said they supported the U.S. Treasury's plan to buy equity in American financial institutions as a means to speed relief to the ailing sector and forestall a financial market meltdown.

Frank said the plan, authorized under the recently passed $700 billion financial rescue legislation, would be more economically efficient than the government buying distressed mortgage-related assets alone.

"We thought it would be economically useful, as it now is, to get healthy banks healthier and also for taxpayer protections, because if you're only buying bad assets the likelihood that the taxpayer will recover the outlay is smaller. Here we are buying equity," said Frank, a Massachusetts Democrat.

U.S. Sen. Charles Schumer, speaking on CNN's Late Edition program on Sunday, urged the Treasury to move quickly on the plan.

"I am hopeful that tomorrow the Treasury will announce that they're doing it. And they have to do it quickly," said Schumer, a New York Democrat.

"This cannot be two, three, four weeks. The markets are waiting, the country is waiting, and we're beginning a downward spiral, not just in finance ... but in the whole economy. We need quick action," he added.

Schumer also said an economic stimulus plan aimed at "main street" America was needed in November, and it should include spending on infrastructure such as roads, water and sewer projects, as well as financial aid to states to prevent them from raising taxes or laying off workers.

(Reporting by David Lawder, Editing by Chizu Nomiyama)