The celebrity chef Neil Perry has hit back at claims his restaurant empire is ripping off migrant workers, insisting the business is operating fully within employment laws.

Some chefs working for Rockpool Dining Group are earning $15 per hour some weeks, well below the minimum wage, while working up to 30 hours’ unpaid overtime, according to Fairfax Media.

Separately, company emails seen by Fairfax tell workers how not to record the hours they worked.

Perry said the Rockpool Dining Group offered Australians and employees on working visas opportunities to learn and grow their skills in restaurants.

“It’s a sad day when a few people try to undermine the amazing work of so many who contribute to making our restaurants great; especially when we operate fully within the employment laws of this country,” he said in a statement on Sunday.

Perry sold Rockpool Group in late 2016, becoming the group’s chief brand and culinary director and a significant shareholder.

Rockpool Group’s chief executive, Thomas Pash, said the Fairfax report was based on questionable documents the company wasn’t allowed to see.

“These allegations are spurious, inaccurate and give an incomplete picture of our practices,” Pash said in a statement.

He said the company’s time attendance system registered hours worked to manage rosters, assign days off in lieu and pay overtime in line with award rates.

“Our permanent employees are remunerated in line with, and in many cases well above, the industry award,” Pash said.

The claims centre on underpayments at two of the group’s restaurants, Sake and Munich Brauhaus.

The workplace minister, Craig Laundy, said he would contact the Fair Work Ombudsman on Monday to ensure they would pursue the journalists who reported the allegations to give up documents proving the claims.

“All allegations of this type irrespective of the name of the business owner and business involved should be followed up and are followed up by the Fair Work Ombudsman,” he told Sky News on Sunday.