Facing a revolt from members of his own party, Australian Prime Minister Malcolm Turnbull has shelved an extradition treaty with Beijing, in a major rebuke to the trustworthiness of China's justice system.

The decision will be closely watched in Ottawa, which agreed last fall to begin talks toward a similar deal with China, although officials have more recently cast doubt on the success of such talks so long as Beijing continues the extra-legal interrogation of corruption suspects.

In Canberra, the Prime Minister's Office pulled the treaty early Tuesday after it became clear it would not survive a vote in the country's Senate. A spokesman expressed disappointment, blaming opposition parties.

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The imminent ratification of the extradition pact, the first between China and a member of the Five Eyes intelligence alliance, had sparked new debate in Australia about the merits of closer ties with a Chinese judicial system the international community has condemned for its use of torture and susceptibility to political interference.

Australian opposition to the extradition deal brought together a coalition of bitter political enemies, as well as some of Mr. Turnbull's own backbench and former prime minister Tony Abbott.

"In my judgment, China's legal system has to evolve further before the Australian government and people could be confident that those before it would receive justice according to law," Mr. Abbott told The Australian on Monday.

Australia's government introduced a legislative instrument to ratify the treaty on March 20, the final step before placing it into effect. Such an instrument is not a bill and does not require a vote to pass – unless legislators vote to disallow it.

But Mr. Turnbull's Liberal government does not possess a majority in the Australian Senate and Cory Bernardi, a senator who recently defected from the Prime Minister's party, led an effort to kill the treaty. He put forward a motion to disallow that was scheduled for debate Wednesday.

By Tuesday morning, however, it became clear that sufficient opposition had gathered to defeat the treaty, and the government backed down. In a statement, Foreign Minister Julie Bishop said the government intends to "continue our discussions with the opposition," citing "the importance of this treaty to Australia's national interest."

Signed in 2007, the treaty contained provisions against extraditing people at risk of torture or execution. But Mr. Bernardi, citing China's 99.9 per cent conviction rate, raised questions about the fairness of Chinese courts and doubts about Australia's ability to enforce promises not to mistreat suspects.

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"We Conservatives will remain vigilant that no such treaty should be ratified by the Australian Parliament until the rule of law improves in China," he said Tuesday.

Australia's "economic future is linked to China. But you don't suspend your own internal judgment, or your own national sense of righteousness, simply for economic reasons," he said in an interview Monday.

Mr. Bernardi is a controversial figure in Australian politics who has opposed same-sex marriage and has been photographed in a red Donald Trump-style "Make Australia Great Again" cap.

In Australia's fractured Senate, Mr. Bernardi was able to play to smaller parties and independent candidates to block the treaty, despite a last-minute attempt by the Prime Minister to defend it.

It "needs to be ratified," Mr. Turnbull said Monday, pointing to the recent interception of a Chinese shipment of more than $100-million worth of methamphetamine destined for Australia. Without legal co-operation between the two countries, the Prime Minister said, those drugs "would have been on the streets in Australia destroying Australian lives."

But the international community has grown increasingly sharp in its condemnation of China's exercise of justice.

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Reports from the U.S. State Department and the United Nations Committee on Torture have called torture a deeply entrenched feature of the Chinese system, in contravention of the country's own laws.

In February, the Canadian embassy in Beijing signed a letter to the Chinese government with representatives of 10 other countries to jointly express concern about what they called "credible claims of torture" of detained human-rights lawyers.

China also maintains an extensive extra-legal system, known as shuanggui, which interrogates graft suspects without arresting them, and uses sleep deprivation and other tactics of psychological torment to extract confessions.

In response to a Globe and Mail report detailing abuses in that system, a senior Canadian official said this weekend that a comprehensive extradition treaty with China is unlikely to succeed if those practices continue.

In Australia, meanwhile, the extradition treaty is unlikely to be revived unless the government can respond to objections raised against it, "which in effect would require aspects of the treaty to be renegotiated," said Donald Rothwell, a top Australian international law scholar at Australian National University.

Renegotiation "is possible in theory, but I cannot speculate on whether the Turnbull government would seek to expend the political and diplomatic capital to do so," he said.

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Ratifying the extradition treaty would have amounted to a show of faith in Chinese justice, said Stuart Clark, a litigator who was president of the Law Council of Australia last year when it published a 30-page report opposing the treaty.

"Australia should not be endorsing, tacitly or otherwise, that system by allowing people to be returned in circumstances where they can't be guaranteed a fair trial," he said.

Shelving the treaty, he said, is "the right decision. There were not appropriate protections. And what is meant to be offered up as a fair trial in China is inconsistent with the concept in Australia."