Citing people familiar with the situation, the newspaper said AUKUS defence ministers will announce on Monday they will launch talks related to “pillar two” of the pact, which commits the members to jointly developing quantum computing, undersea, hypersonic, artificial intelligence and cyber technology.

They are not considering expanding the first pillar, which is designed to deliver nuclear-powered attack submarines to Australia.

AUKUS, unveiled by the three countries in 2023, is part of their efforts to push back against China’s growing power in the Indo-Pacific region.

China has called the pact dangerous and warned it could spur a regional arms race.

The US ambassador in Tokyo, Rahm Emanuel, wrote in an opinion piece in the Wall Street Journal on Wednesday that Japan was “about to become the first additional Pillar II partner”.

A senior US administration official told Reuters on Wednesday that some sort of announcement could be expected in the coming week about Japan’s involvement but gave no details.

US President Joe Biden and Japanese Prime Minister Fumio Kishida will likely discuss expanding AUKUS to include Japan when the president hosts the prime minister in Washington on Wednesday, a source with knowledge of the talks said.

Australia, however, is wary of beginning new projects until more progress has been made on supplying Canberra with nuclear-powered submarines, said the source, who asked not to be identified because they are not authorised to speak to the media.

Australian Defence Minister Richard Marles “has said publicly, and to Japan, that we will seek opportunities to engage close partners in AUKUS Pillar II as our work on critical defence and security capabilities progresses”, said a spokesperson when asked for comment on the FT report.

“Japan is an indispensable defence partner for Australia,” the spokesperson said in a statement.

“Any engagement of additional countries in AUKUS Pillar II projects will be trilaterally decided and announced.”

A spokesperson for the White House National Security Council and China’s foreign ministry did not immediately respond to requests for comment on the FT report.

A Japanese foreign ministry spokesperson said the ministry could not immediately comment.

While the US is keen to see Japanese involvement in pillar two, officials and experts say obstacles remain, given a need for Japan to introduce better cyber defences and stricter rules for guarding secrets.

US Deputy Secretary of State Kurt Campbell said on Wednesday the US was encouraging Japan to do more to protect intellectual property and hold officials accountable for secrets.

“It’s fair to say that Japan has taken some of those steps, but not all of them,” he said.

The United States has said for years that other countries in Europe and Asia are expected to join the second pillar of AUKUS.

The senior US official said any decisions about who would be involved in pillar two would be made by the three AUKUS members, whose defence ministers had been considering the questions for many months, based on what countries could bring to the project.

Campbell said other countries had expressed interest in participating in AUKUS.

“I think you’ll hear that we have something to say about that next week and there also will be further engagement among the three defence ministers of the United States, Australia, and Great Britain as they focus on this effort as well,” Campbell told the Center for a New America Security think tank.

Campbell also said on Wednesday the AUKUS submarine project could help deter any Chinese move against Taiwan, the democratically governed island that Beijing claims as part of China.

Biden, Kishida and Philippine President Ferdinand Marcos Jr are to hold a trilateral summit on Thursday.