(Reuters) - The U.S. House of Representatives on Wednesday approved a measure to delay by six months the Obama administration’s rule to extend mandatory overtime pay to more than 4 million workers, despite a White House promise to veto the bill.

The House passed the legislation on a partisan vote of 246-177, with just 5 Democrats joining 241 Republicans in favor of moving the rule’s effective date from Dec. 1 to June 1.

The rule will require employers to pay overtime to salaried workers earning less than $47,500 a year, double the current threshold of $23,660. Republicans and business groups argue the rule will force employers to demote salaried workers to hourly positions and create more part-time jobs.

The White House said on Tuesday that President Barack Obama would veto legislation delaying the rule.

“While this bill seeks to delay implementation, the real goal is clear - delay and then deny overtime pay to workers,” the White House said in a statement.

The Republican legislation also faces likely opposition by Senate Democrats who could block it from advancing in that chamber. But for some Republicans campaigning for re-election, voting for the bill gives them an opportunity to tout their opposition to the rule in their home districts.

Opponents have also launched a legal challenge to the rule. Texas and 20 other states, as well as the U.S. Chamber of Commerce and other business groups, filed separate lawsuits in federal court in Texas last week claiming the U.S. Labor Department abused its authority with its drastic increase of the salary threshold.