President Barack Obama will seek to increase the number of people who earn overtime pay by updating regulations that exempt broad swaths of supervisors, managers and office workers from making overtime, a White House official said on Wednesday.

On Thursday, Obama will ask the Labor Department to look at regulations for overtime, and whether to hike the salary threshold above which employers are not required to pay overtime. The threshold was last raised in 2004 to $455 per week.

It is another in a series of populist measures Obama is promoting ahead of November midterm elections as Democrats try to appeal to voters and keep control of the Senate.

Obama has been campaigning to boost the minimum wage to $10.10 per hour from $7.25, a measure that stands little chance of passing Congress. He also has tried to urge Congress to extend unemployment insurance benefits for people out of work for extended periods.

But his administration does not need congressional approval to define who is exempt from overtime pay, the White House said.

"Some employers classify workers as 'white collar' workers even though the overwhelming majority of their duties are not white collar," a White House official said on condition of anonymity, using the example of a convenience store manager or shift supervisor at a fast food restaurant.

"It's even possible that some of these workers make less than the minimum wage per hour," the official said. A salaried worker earning $455 per week who works 63 hours or more earns less than the minimum wage.

California has a higher threshold of $640 per week and is set to boost that to $800 per week in 2016, while New York set its threshold at $600 per week, increasing to $675 per week in 2016, the White House official noted.