By David Ljunggren

OTTAWA (Reuters) - Canadian Prime Minister Justin Trudeau sidestepped questions on Tuesday on the sensitive topic of possible extraditions to China, saying Canada would stick to high standards when deciding whether to return Chinese citizens.

A statement posted on Trudeau's website said his national security adviser went to Beijing last week and agreed to start talks about an extradition treaty as part of a security dialogue. China, which wants the return of officials suspected of corruption who it says are hiding in Canada, has long pressed for such a treaty.

Some Western countries are reluctant to sign extradition deals with China, partly out of concern about the integrity of its judicial system and treatment of prisoners.

Some people convicted of corruption face the death penalty. Canada refuses to send people to countries without assurances they will not be executed.

"Extradition is certainly one of the things the Chinese have indicated they want to talk about," Trudeau told a televised news conference at the United Nations.

"As everyone knows, Canada has very high standards in terms of extradition treaties in accordance with our values. But we're happy to have a high-level security dialogue," he said.

News of the Beijing meeting revived speculation Ottawa had made concessions to secure the return of Kevin Garratt, a Canadian citizen convicted of spying, whom China deported last week. Canadian officials insist there was no deal.

Garratt's release was widely seen as a triumph for Trudeau, who visited Beijing earlier this month in a bid to seal closer economic ties. Chinese Premier Li Keqiang arrives in Canada on Wednesday for the start of a three-day trip.

The opposition Conservative Party, long suspicious of China's human rights record, accused Trudeau of abandoning Canadian principles.

"Does the prime minister not understand that our openness to China should be about encouraging China to adopt our values for human rights, as opposed to us giving in to China's?" interim party leader Rona Ambrose told the House of Commons.

China does not have extradition treaties with the United States, Australia or Canada, which according to state media are the most popular destinations for suspected economic criminals from China.

(Reporting by David Ljunggren; Editing by Peter Cooney)