South Africa's trade minister Parks Tau said he was optimistic that the United States' flagship trade initiative with Africa, which expires later on Tuesday, would be renewed.

Tau's office said in a statement that the overall message from the minister's recent trip to the United States was that there was "broad support for the renewal of AGOA (the African Growth and Opportunity Act) in Congress across the aisle".

"On the period of renewal for AGOA, the consensus suggests that AGOA may be renewed for a short-period of between one-to-three years to allow Congress to introduce changes and improvements to the programme," the statement said.

The priority for South Africa is to get AGOA extended even if it is just for a short period, Tau added.

South Africa is trying to persuade President Donald Trump's administration to lower the 30% tariff imposed in August on its exports to the U.S.

Tau met US Trade Representative Jamieson Greer this month in Washington as part of the negotiations to reduce the tariff.