Pizza Hut underpaid workers: FWO

Pizza Hut has been slammed by an employment watchdog for not heeding warnings to ensure its staff was being paid lawful wages.

The criticism comes after the Fair Work Ombudsman found a franchise in Newcastle underpaid 24 vulnerable workers almost $20,000.

The employees, mostly juniors and international students, were paid low, flat rates that undercut their minimum wage.

The revelation comes just months after an ombudsman compliance activity found "widespread issues" with the treatment of delivery drivers in a review of 34 Pizza Hut franchises in January - resulting in legal action.

The owner of the Newcastle outlet told ombudsman inspectors he was operating his first business since immigrating to Australia and had not received training on his obligations under workplace laws from the Pizza Hut head franchisor.

Fair Work Ombudsman Natalie James says the watchdog is worried about the lack of response from Pizza Hut since it published its concerns earlier in the year.

"If this non-compliance is replicated across the Pizza Hut network to the same extent of the delivery drivers, it would represent a significant failure to provide lawful wages and entitlements to the Pizza Hut workforce," she said in a statement on Friday.

Pizza Hut has been contacted for comment.