A U.S. Senate vote to extend the popular cash for clunkers auto sales incentive could be pushed to Saturday if lawmakers cannot agree on the measure, Senate Majority Leader Harry Reid said.

There's a significant majority that wants to move forward with this legislation, Reid said Wednesday. That being said, there's some people who still don't like the program.

Lawmakers have scrambled to extend the popular program after an unexpected avalanche of business exhausted the initial $1 billion approved for the program.

Federally backed rebates of up to $4,500 to consumers who trade in old, gas-guzzling vehicles and buy new, fuel-efficient ones helped boost industry sales in July to a 2009 high.

The House of Representatives approved a $2 billion extension last Friday, and Reid has said the measure has enough votes to pass the Senate before the chamber leaves for August recess.

Reid said he would move to cut off debate on the measure on Wednesday evening if he could not reach an agreement with Republicans, which could push back a final vote until Friday or Saturday under the Senate's procedural rules.

Transportation Department figures showed sales nearing 160,000 vehicles in connection with the program, representing more than $450 million in federal vouchers since July 1. But with more deals in the pipeline, the government said the existing funds would quickly be exhausted.