Nasser Al-Tuwaim also threatened to sue and defame merchants who unjustifiably increase their prices, Al-Riyadh daily reported.

Saudis and residents paid about SR450 million for rice given as zakat to the poor in the last few days of Ramadan.

Al-Tuwaim also said the society would soon classify restaurants according to the service they provide to customers. He added that the CPS would also call for harsher punishments for violating merchants who inflate prices of goods and services.

On Saturday a number of importers of high-quality rice reportedly sent letters to the Commerce Ministry containing the names of individuals and companies who used their brand names and trademarks on bags containing sub-quality products.

The ministry also said it had confiscated large quantities of rice in packages carrying genuine trademarks, adding that foreign residents had probably put it in to sell on at low prices.

The trade fraud committee at the Riyadh Chamber of Commerce and Industry denied that sub-quality rice was being sold to restaurants but said commercial fraud was on the rise.

A number of Asian expatriates were reportedly caught running big warehouses containing large quantities of sub-quality rice in bags carrying the names of established companies.