NAIROBI (Reuters) - African manufacturers are lobbying U.S. Congress to grant a last-ditch extension of one or two years to a duty-free trade programme due to expire at the end of September, a Kenyan factory owner involved in the campaign told Reuters.

U.S. President Donald Trump's aggressive tariff policies have cast doubt on the prospects for renewal of the African Growth and Opportunities Act (AGOA) trade initiative, which was passed in 2000 under former President Bill Clinton to provide duty-free access to the U.S. market for thousands of products.

Delegations from Kenya and four other AGOA beneficiaries visited Washington last week to push for the temporary extension, said Pankaj Bedi, chairman of apparel company United Aryan, which supplies U.S. retailers such as Target ( TGT ) and Walmart ( WMT ).

The act is designed to support economic development of African nations and supports hundreds of thousands of jobs in the textiles, automotive and mining sectors while U.S. lawmakers have viewed it as a tool to counter Chinese influence on the continent.

Despite bipartisan support, an attempt last year to renew AGOA for 16 years did not make it to a vote in Congress. Since then, President Trump's trade policies have suggested there may not be the political will in Washington to push through an extension.

Bedi, who is also a Kenya Association of Manufacturers board member, said the delegation of private investors and government officials had more than 30 engagements last week, including with members of Congress and their aides.

He said there was universal support from the Congressional Republicans and Democrats they met, including staffers for House Speaker Mike Johnson, to renew AGOA.

But he said it remained unclear whether Congress could find a piece of legislation in the next two weeks to which a renewal could be attached.

Without an extension, manufacturers would face steep rises in tariffs on their products, including a jump from 10% to 43% for synthetic textiles.

"It's like a house of cards that will collapse," Bedi said, predicting mass layoffs across the textiles sector if AGOA is not renewed.

The White House and the offices of the United States Trade Representative and Speaker Johnson did not respond immediately to requests for comment. The White House has not said publicly whether it supports an extension.

Bedi said that if AGOA ends, the U.S. would become even more heavily dependent on Asian manufacturers.

"If this is taken away, by default, the business is going to go back to China," he said.