Rishi Sunak has declared China is the “biggest state-based threat to our economic security” as he refused to rule out sending more arms to Taiwan.
The PM is attending a G20 summit in Indonesia alongside world leaders including Chinese president Xi Jinping.
Speaking to journalists, Mr Sunak warned that Beijing “poses a systemic challenge to our values and interests”.
“China is undoubtedly the biggest state-based threat to our economic security,” he said. ‘I think that view, by the way, is highly aligned with our allies.”
But Mr Sunak suggested it was important to hold talks with the Chinese on global problems.
“China is an indisputable fact of the global economy and we’re not going to be able to resolve shared global challenges like climate change, or public health, or indeed actually dealing with Russia and Ukraine, without having a dialogue with them,” he went on.
Mr Sunak said he was considering how to respond to Chinese threats to Taiwan. Asked whether he thought Britain should learn lessons from Ukraine by sending arms now so it is in a better position to protect itself in case of invasion, he said: “We’re looking at all of these policies as part of our refresh of the integrated review.
“Our policy on Taiwan is obviously there should be no unilateral change to the status and there should be a peaceful resolution to that situation. We stand ready to support Taiwan as we do in standing up to Chinese aggression.”
Taiwan, which is located 100 miles off the coast of mainland China, sees itself as an independent country with its own democratically-elected leaders.
But Beijing views it as a breakaway province that will eventually be under its control.
President Xi has said "reunification" with Taiwan "must be fulfilled" and has not ruled out the possible use of force to achieve this.
In September, US President Joe Biden vowed that the US would defend the island if China attacked.
The G20 is made up of 19 nations and the EU. The member countries are Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the UK and the US.
Mr Sunak is expected to hold one-on-one talks with several of the leaders including Mr Biden, who he will meet for the first time. It has not been confirmed whether he will meet President Xi during the two-day summit.