The United States and Taiwan have agreed to start trade talks under a new initiative, saying they wanted to reach agreements with "economically meaningful outcomes", in another sign of stepped up US support for the island.

Both sides unveiled the US-Taiwan Initiative on 21st-Century Trade in June, just days after the Biden administration excluded the Chinese-claimed island from its Asia-focused economic plan designed to counter China's growing influence.

The office of the US Trade Representative said the two sides had "reached consensus on the negotiating mandate" and it was expected that the first round of talks will take place early this autumn.

"We plan to pursue an ambitious schedule for achieving high-standard commitments and meaningful outcomes covering the eleven trade areas in the negotiating mandate that will help build a fairer, more prosperous and resilient 21st-century economy," Deputy United States Trade Representative Sarah Bianchi said in a statement.

The negotiating mandate released along with the announcement said the US and Taiwan have set a robust agenda for talks on issues like trade facilitation, good regulatory practices, and removing discriminatory barriers to trade.

It said the start of the formal talks would be for the purpose of reaching agreements with "high standard commitments and economically meaningful outcomes".

It did not mention the possibility of a broad free trade deal, which is something Taiwan has been pressing for.

The US, despite the lack of formal diplomatic ties, has been keen to bolster support for Taiwan, especially as it faces stepped up political pressure from China to accept its sovereignty claims.

China-US relationship 'rattled' in face of global turmoil

It comes as the US's top envoy in East Asia said it expects China to ramp up its military, diplomatic and economic "coercion" of Taiwan, after Beijing's unprecedented drills around the island it claims as its own.

The Chinese military has staged days of air and sea exercises in the Taiwan Strait after visits by US House Speaker Nancy Pelosi and a congressional delegation to the self-ruled island.

"While our policy has not changed, what has changed is Beijing's growing coercion," Daniel Kritenbrink told reporters on a teleconference call.

"These actions are part of an intensified pressure campaign... to intimidate and coerce Taiwan and undermine its resilience," he said.

The US believes the drive to press the island's government will carry on in the coming "weeks and months", he added.