The comments follow talks for London to access the 150-billion-euro ($174 billion) European Union rearmament loan scheme ending in failure last year amid disagreement over the entry fee.

On the sidelines of a visit to China this week, Starmer told reporters he remained open to exploring closer cooperation.

"I do think that both on spending, on capability and cooperation... we need to do more together," the UK leader said.

"I have made the argument that that should require us to look at schemes like SAFE and others, to see whether there isn't a way in which we can work more closely together."

European nations have scrambled to boost their militaries since Russia's 2022 invasion of Ukraine, with Brussels launching the SAFE (Security Action for Europe) lending initiative in response.

Created to provide EU countries with loans at lower rates to help them rearm, London and Brussels wrangled for months over the level of contribution Britain would make to join but failed to seal a deal.

It was a setback in Starmer's bid to rebuild post-Brexit relations with the EU since winning power in July 2024, hoping to fire up Britain's insipid economy.

London and Brussels struck a strategic partnership agreement last May, which included a pact to deepen defence cooperation as well as measures to boost trade.

EU Trade Commissioner Maros Sefcovic will be in London Monday to meet with several UK ministers, ahead of the next bilateral summit scheduled for later this year.

Starmer has ruled out rejoining the 27-member bloc's customs union, favouring closer ties with its single market.

"I think there are other areas in the single market where we should look to see whether we can't make more progress," he said during this week's overseas trip.

"That will depend on our discussions and what we think is in our national interest. But what I'm indicating here is -- I do think we can go further."

The centre-left Labour leader also indicated that negotiations continue on a youth mobility program that would include a cap on the number of visas granted and the length of authorised stays.

London and Brussels have already reached an agreement for Britain to rejoin the bloc's popular Erasmus student exchange programme, starting in 2027.