Prices of basic commodities should be regulated to benefit poor consumers, Cosatu general secretary Zwelinzima Vavi said on Thursday.

"Competition alone cannot reduce prices in a manner that benefits the majority of our people. Consumers do not always have adequate information to make decisions in relation to where to buy and not to buy," he said in a speech prepared for delivery at the Competition Commission's 15th anniversary in Johannesburg.

"Even in instances where they have information of better prices there are transport costs involved... This is why a consideration should be made to regulate prices of basic commodities."

Vavi said the South African economy was "highly concentrated" which made collusion by companies easy.

"This is why Cosatu has been consistently calling for the diversification of the economy to allow more local suppliers to emerge, which would benefit consumers through lower prices and create more jobs.

"The state should also get more involved as producer of goods and services to help bring prices down."

Vavi also congratulated the commission on its anniversary.

"In these 15 years it has done a sterling work in addressing the problems of collusion, price fixing, abuse of dominance and market allocation."