The International Monetary Fund (IMF) gave its full backing to South Africa's land reform plan on Thursday, as long as the highly contentious process is transparent and based on the constitution.

The Fund's senior resident representative in South Africa Montfort Mlachila told Reuters that the reform must not damage farm output to ensure South Africans continue to have reliable food supplies.

President Cyril Ramaphosa has said the ruling African National Congress (ANC) plans to change the constitution to allow the expropriation of land without compensation, as most of it is still owned by members of the white minority.

"We are in full support of the need to undertake land reforms in order to address the issues of inequality," Mlachila said in an interview.

Nearly a quarter century after the end of apartheid, the country remains racially divided and unequal, and the ANC plan aims to improve the lives of the many poor black South Africans.

The debate erupted again last week when US President Donald Trump said he had asked Secretary of State Mike Pompeo to study South African "land and farm seizures" and the "killing of farmers". South Africa accused Trump of stoking racial divisions.

Speaking at his office in Pretoria, Mlachila said the IMF was not an expert on land reform. However, he said: "There is need to have a transparent, rules-based, and constitutional process that leads to desirable outcomes. It is particularly important not to undermine agricultural production and food security."

Ramaphosa has said any measures would not hit economic growth or food security. No land has been "seized" since the ANC resolved to expropriate land without compensation at a party conference in December.

British Prime Minister Theresa May has also supported the programme, provided it is carried out legally.

Commenting on the South African economy, Mlachila said the IMF was unlikely to revise its growth forecast upwards. Last month the Fund kept its prediction for 2018 growth at 1.5%.

"Given the weaknesses in growth indicators in the second quarter of 2018, I don't see us revising upwards," he said, although he added that it was too early to say for definite.

Ramaphosa's election in February initially buoyed investors' confidence but poor economic data, including the worst quarterly GDP contraction in nine years in the first quarter, have eroded some of the enthusiasm.

Mlachila said South Africa was not expected to seek IMF financial support due to its deep domestic financial markets and access to international markets for financing its balance of payments and fiscal deficits.

"We really don't see much need for recourse to financing from the IMF," Mlachila said.