Close to half the South African population does not want the country's Constitution changed, a study has shown.

"Almost 46 percent of South Africans believe that our Constitution is the basic law of the land and should not be changed," research company Ipsos said in a statement on Monday.

Spokeswoman Mari Harris said recent calls for changes to section 25 of the Constitution, which deals with land expropriation and compensation, had sparked much debate.

Sixteen percent of the 3565 people surveyed believed the Constitution could be changed, while almost 28 percent remained neutral on the subject. Ten percent did not know.

The poll was conducted between April and May this year.

There were mixed views on the effect changes to the Constitution would have. At least 41 percent believed changing it would limit the freedom of South Africans. Broken down along political party lines, the figure among Democratic Alliance supporters was 46 percent, with 42 percent of ANC supporters holding this view.

Overall, 33 percent of people questioned felt the Constitution in its present form was slowing transformation.

"This view that the Constitution is hampering transformation is likely influenced by numerous requests to change some aspects of it by the ANCYL and Numsa, as well as significant writing on the subject in the SA media over the past year," Harris said.