Former president FW de Klerk warned President Jacob Zuma on Tuesday against changing the Constitution to enable the national government to rein in the powers of the provinces.

"I emphasised the necessity, which I firmly believe, that we should not in any way undermine the historical compromise which is encapsulated in our Constitution," he told reporters after a private meeting of more than an hour with Zuma at Tuynhuys.

De Klerk said he had raised the issue of the Constitution 17th Amendment Bill, which controversially gives national government far-reaching powers to intervene in municipalities.

Critics say this will in effect severely undermine the power of provinces as set out in the Constitution.

"We struck a balance between becoming a federalised state and a centralised one. There is a hybrid somewhere in between a federalised state and a centralised state and I believe it is very important that delicate balance should not be disturbed."

The FW de Klerk Foundation has sharply criticised the bill, as has the Democratic Alliance which described it as an attempt to "entrench the hegemony" of the African National Congress across South Africa.

The bill was approved by Cabinet on the eve of the April elections.

De Klerk said he and Zuma had discussed "a number of issues that are burning at the moment but that remains between us" and had agreed on the need to work to alleviate the plight of the poor.

"We must address the lot of the almost 50 percent of our population who are suffering, who live on or below the breadline."

Zuma said the "warm and friendly" discussion had taken place at De Klerk's request and he would be happy to meet with him again.