SYDNEY, April 12 (Reuters) - Australia and the United States have committed more than A$5 billion (US$3.5 billion) to support a range of vital minerals projects, nearly double the amount pledged when the two countries signed a cooperation agreement six months ago, Canberra said on Sunday.

The funding is intended to support Australian projects to develop and refine minerals vital to industries, including defense, advanced manufacturing and the energy transition, a market long dominated by China.

When the two countries signed a framework agreement last October, they stated that they would thereby support the rebuilding of the high-tech manufacturing base in the United States, while helping to "counter China's export dominance and ensure the resilience of Western supply chains."

In that agreement, Australia and the United States agreed that each would provide investments of at least $1 billion in priority critical minerals projects in both countries worth $8.5 billion over the next six months.

Australia has huge supplies of vital minerals such as rare earth elements, but China has mastered the technically difficult and environmentally risky refining process.

"Australia and the United States are fulfilling commitments made at the White House, through priority projects in Australia that support the production of rare earth elements and vital minerals," Resources Minister Madeleine King said in a statement.

She added, "Australia is taking the lead globally in diversifying vital supply chains for critical minerals and rare earth minerals, which are essential to supporting the economic and national security of Australia and our trading partners."

The $5 billion Australian dollar financing will be provided through the Australian Export Finance Agency and the US Export-Import Bank.

(US$1 = 1.4164 Australian dollars)