The public protector should investigate Police Minister Nathi Mthethwa to see whether he contravened ethics by staying in expensive hotels, the Independent Democrats said on Tuesday.

"It has been alleged that the minister has spent in excess of R700 000 on accommodations for himself and unknown guests and/or staff at two five star luxury hotels in Cape Town and Durban," read an extract of a letter from the ID's police spokesperson Haniff Hoosen to the public protector.

Hoosen believes the public protector must investigate whether Mthethwa has contravened provisions of the Code of Ethics for Ministers and Deputy Ministers.

He also wants a change in the way the Ministerial Handbook is approved.

"The Cabinet's powers to approve the handbook must be taken away. Perks, privileges and allowances for ministers should be determined by a similar process to the Moseneke Commission," he suggested.

That commission examined remuneration for public office bearers.

"It is precisely because ministers have determined their own benefits that we have gotten into this mess in the first place," Hoosen claimed.

According to recent reports in the Sunday Independent and Sunday Times, some of the bills included Christmas and New Year at the Hilton Hotel in Durban, a stay the night before Valentine's Day, and a stay in Cape Town's five-star Table Bay Hotel.

His spokesman Zweli Mnisi said the stays were due to roadshows, elections and flood damage at his home.