JOHANNESBURG (Reuters) -South Africa is preparing a last-minute "enhanced" trade proposal at the urging of U.S. officials in hopes of avoiding a 30% tariff which kicks in on Friday, its trade minister said on Thursday.

South Africa initially submitted a proposed trade deal to President Donald Trump's administration in May and revised it in June, but received no response.

"We're having to navigate a last-minute proposal that's enhanced from the proposal that we had initially given," Trade Minister Parks Tau said on South Africa's 702 radio, adding: "And to tell the truth, it's wait and see."

The countdown to the August 1 deadline has stirred fear and uncertainty in South Africa, where the central bank governor has estimated a 30% U.S. tariff would put 100,000 jobs at risk, with the agriculture and automotive sectors hit hardest.

The U.S. is South Africa's second-largest bilateral trading partner after China. South Africa exports cars, some manufactured goods, citrus fruits and wine to the U.S.

Tau said South Africans spoke to U.S. officials on Wednesday night, both at the level of Washington's embassy in Pretoria and also the U.S. trade representative, but uncertainty lingered on what would happen as the tariff deadline approached.

"They (said) they would encourage us to resubmit our proposal, possibly an enhanced proposal, to the United States government," Tau said.

A top South African diplomat said on Tuesday that U.S. demands on domestic affirmative-action policies were complicating efforts to secure a trade deal.

Bilateral relations have been strained by South Africa's Black Economic Empowerment (BEE) policies to address the legacy of centuries of racial inequality and its genocide case against Israel at the World Court, which Israel and the U.S. vehemently oppose.