Iran has said it will wait for an official response from US negotiators after President Donald Trump rejected a proposal to reopen the Strait of Hormuz to commercial shipping within seven days.

In a post on Telegram, Iranian Foreign Minister Abbas Araghchi acknowledged Trump's rejection, but accused the president of previously making contradictory statements.

Earlier, Trump told reporters at the White House that Tehran's proposal was not "acceptable" and that they wanted to make a deal to open the strait immediately because "they're losing so badly".

On Friday at the UN, Araghchi told reporters that an agreement could be reached if "necessary conditions are met" between the two countries.

Araghchi said the conditions to open the strait were the same that had been included in a memorandum of understanding between the US and Iran that was signed in June.

Iran said it had raised reopening the strait and ending hostilities during negotiations on the sidelines of the UN General Assembly in New York this past week.

The vital waterway through which around a fifth of the world's gas and oil supply usually flows has been effectively closed since the outbreak of war in February.

"I'm rejecting their deal," Trump said on Saturday, adding that the US already had "total control" of the strait, with "massive amounts of oil" passing through it.