Changes to be announced in the Budget will mean that UK businesses can access state-backed UK Export Finance loans to bring in critical minerals.
The Chancellor is particularly keen to encourage greater trade with Australia, a major ally which has large deposits of lithium, which is used in batteries.
It comes as Downing Street said that the Commonwealth can be used as a bulwark against China’s influence in the Indo-Pacific region.
Sir Keir Starmer will press leaders of the club to deepen economic and defence ties as he attends its bi-annual summit in Samoa this week.
Beijing is seeking to wield ever increasing influence, including through its participation in the Brics trade bloc alongside Russia, Brazil and South Africa.
The Prime Minister’s spokesman said: “The Pacific is a crucial area for the geopolitics and security and economic interests.
“We believe the Commonwealth has a huge potential to build shared resilience in the face of today’s global challenges.”
Sir Keir’s bid for closer ties with Canberra was boosted by the announcement that an Australian pension fund will invest up to £1bn in the UK.
Aware Super said it planned to pump the money into the British property market.
At the same time AustralianSuper, the country’s largest pension fund, said it planned to manage £250bn from its London office by 2035.
Sir Keir said: “These investments are a major vote of confidence in the UK, and in this Government.
“I am determined to ensure that the UK is the best place in the world to invest and do business, so we improve the lives of hard-working people.
“By attracting strong, sustained investment, we will also build the expertise we need to drive innovation, stay ahead of the global game, and support economies around the world with British-backed projects.”