Employers who underpay workers will face stiffer penalties in a proposed crackdown should the Turnbull government be returned on July 2.

The Fair Work Ombudsman will receive $20 million in additional funding and stronger powers so it can deal more effectively with employers who exploit staff.

Employment Minister Michaelia Cash says the 7-Eleven chain is probably the most well-known offender in recent times.

“Unfortunately (it) is by no means the only one,” she said in a statement, announcing the government’s policy to protect vulnerable employees.

Labor employment spokesman Brendan O’Connor questioned the timing of the proposal during an election campaign and even then, said he doesn’t believe it goes far enough.

“We introduced a private member’s bill that went to these issues … because the government wasn’t acting,” he told Sky News.

“They established a task force in August last year, nothing happened.”

Greens MP Adam Bandt is also skeptical the changes would have helped 7-Eleven workers or prevent future widespread exploitation in franchises because there is a “big loophole” in the plan.

Head offices will be responsible for the pay of their franchise’s employees but will be let off the hook if they’ve given their franchisees an “education session”, he says.

“Giving more resources to the Fair Work Ombudsman is a good idea but there’s no point giving the watchdog more teeth if the watchdog can’t bite head office,” Mr Bandt said in a statement.

But Master Builders Australia believes the plan achieves a reasonable balance between the interests of workers and employers.

“Employers who do not provide the correct entitlements to workers should be condemned,” its chief executive officer Wilhelm Harnisch says.

“But those who make a genuine mistake, particularly small businesses, shouldn’t suffer onerous penalties.”