Australia is putting its friendship with Japan at the expense of the relationship with China, claims the federal Opposition.

But Prime Minister Tony Abbott denies the government is playing a "zero-sum game" with Australia's relationships.

It follows comments by Foreign Minister Julie Bishop, who is vowing to be direct with Beijing because "China doesn't respect weakness."

"This Government will stand up and defend our national interest," the minister told AM.

"We have an open export-orientated market economy, we are an open and free democracy committed to the rule of law and international norms.

"That's who we are and that's what we'll protect."

She added that it was better to be "clear and direct" about Australia's positions to avoid "confusion" or "misunderstanding".

Labor's foreign spokeswoman Tanya Plibersek says she is "dismayed" the government is getting friendlier with Tokyo at the expense of Beijing.

"This has been a continuing theme in the Government's foreign policy recently - this zero-sum game approach to our friendships in the region," Ms Plibersek told reporters in Sydney.

Ms Plibersek accused Ms Bishop of acting like a foreign policy commentator instead of a minister.

"I think the comments today reflect loose language that is quite counterproductive," she said.

But Mr Abbott said the Government was focused on both relationships.

"When it comes to international friendships it's not a zero-sum game," he told reporters in Perth.

"It is possible to strengthen a range of friendships simultaneously.

"We want a better friendship with Japan and I think pretty obviously we're getting that, but we also want better friendship with China."

His comments follow the three-day visit by Japan's prime minister Shinzo Abe, who used his speech to parliament to highlight greater economic and security co-operation with Australia.

The speech, as well as Mr Abbott's own address welcoming his Japanese counterpart, has both been attacked by China's state-owned news agency Xinhua.

The foreign minister's parliamentary secretary Brett Mason said it should not be seen as "provocative" or "out of order" for Australia to stand up for its interests.

He said it was common for some in China to be worried by Australia's security ties with Japan and vice versa.

The Government has said it is "reasonably optimistic" of reaching a free trade deal with China by the end of the year.