Najib Abdul Razak is opposing the United States government’s bid to stay a court order for Goldman Sachs and its former banker Tim Leissner to supply documents and testimony vital to his defence against 1MDB-linked criminal charges in Malaysia.

The former prime minister’s legal team in New York is relying on the allegation that the US administration was in cahoots with the Wall Street investment bank to prevent him from accessing the much-needed material...