Australian billionaire James Packer said on Thursday that Australia must strengthen ties with China as more than 300 million Chinese middle-class consumers present an enormous opportunity for Australia's tourism, financial and services sectors.

"Foreign investment, foreign workers and migrants are part of this country's proud history; in fact they built this great country we live in," he told a business lunch in Sydney.

Packer urged Australian political leaders to curb their rhetoric on "the issue of foreign and domestic affairs" during the federal election campaign.

He said some of the recent public debate had played on fears and prejudices, sending the wrong messages overseas.

The casino boss gave his endorsement to Australian Foreign Minister Bob Carr.

"Bob Carr truly understands China and won't waive in putting Australia's interest first," Packer said.

"I urge whoever wins the next federal election to ensure Bob Carr is at the forefront of our diplomatic relations with China," he said.