The chairperson of South Africa's ruling African National Congress (ANC) Gwede Mantashe was quoted as saying the state should take without compensation land from those who own more than 12 000 ha, comments that sent the rand weaker.
More than two decades after the end of apartheid, white people still own most of South Africa's land.
Ownership patterns remain highly emotive as the government has been slow to transfer land to the black majority after centuries of colonial and racial oppression.
The ANC's plans to amend the constitution to redistribute land have been interpreted negatively by some investors, who see them as undermining property rights.
The ruling party has sought to assuage those fears by saying that land reform will follow a parliamentary process.
"You shouldn't own more than 12 000 ha of land and therefore if you own more, it should be taken without compensation," Mantashe, who is also the country's mines minister, told the News24 website in an interview published on Wednesday.
It was not immediately clear whether Mantashe's comments represented official ANC policy. Four key party officials did not answer their phones when called by Reuters for clarification.
Mantashe is one of the top six most powerful officials in the ruling party and a close ally of President Cyril Ramaphosa.
The rand fell more than 3% against the dollar earlier, partly weakened by Mantashe's comments, a report by Moody's ratings agency on the struggling economy and a resurgent dollar, which struck a 13-month peak.
The ANC is under pressure to make headway with land reform ahead of next year's national election, where the ultra-left Economic Freedom Fighters party has made faster land redistribution one of its main policies.
The 12 000 ha land ownership limit was mooted in 2016, by then-rural development minister Gugile Nkwinti, but Nkwinti said the government would seek to buy, not expropriate without compensation, land from those owning more than 12 000 ha.
AfriForum, an organisation that mostly represents white South Africans on issues such as affirmative action, has criticised the ANC's decision to endorse constitutional changes to allow the state to seize land without compensation, saying the move would be "catastrophic".