Huseyincan Celil, an ethnic Uighur and a rights activist, is on trial on terrorism charges in Urumqi in Xinjiang, home to a Muslim majority.
His wife told the BBC that relatives in the courtroom say he told the court he had been tortured by secret police.
Mr Celil also holds Chinese nationality and is being tried as a Chinese.
An unnamed official told the Reuters news agency that Canadian Foreign Minister Peter McKay had also said he was unhappy that Canadian diplomats failed to witness court proceedings.
But Secretary of State for Foreign Affairs Helena Guergis said Canada was continuing to make representations to the Chinese authorities.
"Our requests for information and trial dates have gone unanswered, but embassy officials are in daily contact and they are en route to the province where Mr Celil is being held to deal directly with court officials and secure access to court proceedings," she said.
Mr Celil was an imam who left China in the 1990s. He arrived in Canada in 2001 as a refugee and was given Canadian citizenship. This is not recognized by China.
He travelled to Uzbekistan last year, where he was arrested and then extradited to China on terrorism charges in March 2006.
His wife Kamila Telendibaeva held a news conference in December about her husband's plight.
"It's very sad. I need to get some information about my husband," she told reporters.
Amnesty International says Mr Celil is one of thousands of Uighurs being wrongly prosecuted by China.
Xinjiang, home to the Uighurs and other minorities, has long desired autonomy from Beijing, which regards the province as a home to terrorists.