Australia's Resources Minister Martin Ferguson backed stronger investment links with China on Thursday, as Australia considers China's $19.5 billion tie-up with Anglo-Australian miner Rio Tinto Ltd.

Two opinion polls in the past week point to growing public concern in Australia about China buying into its resource firms, while Greens, independent and rural-based National Party politicians have also spoken out against growing Chinese influence.

But Ferguson cautioned against a retreat to protectionist policies.

"This is no time for a retreat to protectionism or xenophobia," Ferguson said in a speech to the mining industry in the southern city of Melbourne on Thursday, adding Australia's industry needed to prepare for a return of global growth.

Ferguson was backed by Assistant Treasurer Chris Bowen, who on Thursday said most foreign investment from China was in Australia's national interest.

"As a country rich in resources, we need some foreign investment to develop those resources," Bowen wrote in an opinion piece in Thursday's Sydney Morning Herald newspaper.

"Most foreign investment, including that from China, is in our national interest, especially at a time like this. It creates jobs," he said, adding China's economic rise was good for both China and countries which engage with China.

Treasurer Wayne Swan is considering whether to approve Rio's link up with China's State-owned Chinalco, which includes Chinalco taking an 18 percent stake in the global miner.

Swan last week gave foreign investment approval to a $438 million Chinese investment in iron ore miner Fortescue Metals Group, but rejected on national security grounds an investment by another State-owned Chinese firm, Minmetals, in Australian miner OZ Minerals.

A revised Minmetals deal with OZ which addresses those national security concerns is now being considered by the government.

Ferguson said China's interests in Australian resources were no different to previous interest from Japan, Australia's largest export market.

He said Australia encouraged foreign investment, and the decisions on Fortescue Metals, and on Minmetals and Oz Minerals, proved each investment proposal was decided on its individual merit against national interest criteria.