HALIFAX - Prime Minister Stephen Harper says he will continue championing the cause of human rights in China despite warnings from a Chinese official that it could hurt Canada's trade relations.

Harper, speaking to reporters Friday in Halifax, was responding to comments from He Yafei, the country's assistant minister of foreign affairs for North America, who warned Thursday that renewed criticism could erode trust between the nations.

The case of dual Chinese-Canadian citizen Huseyin Celil, who has been jailed in China, has been a rising irritant between the two countries.

Harper said his government believes there's no clear evidence that Celil, a minority rights activist, has committed any crimes or participated in alleged terrorism.

"There are those in the Opposition who will say, 'You know, China is an important country, so we shouldn't really protest these things . . . so maybe someday we'll be able to sell more goods there,'" Harper said.

"I think that's irresponsible. I think the government of Canada, when a Canadian citizen is ill-treated and when the rights of a Canadian citizen need to be defended, I think it's always the obligation of the government of Canada to vocally and publicly stand up for that Canadian citizen.

"That is what we will continue to do."

Celil was apparently travelling with a Canadian passport in Uzbekistan when he was picked up and taken to China.

Harper described the move as illegal.

"They continue to deny his Canadian citizenship, which was granted under our law and international law," Harper said.

"So we continue to protest this at every level, up to and including my own (recent) meeting with the president (of China). We will continue to vocalize these concerns."

Harper said Chinese officials should keep in mind that China enjoys a huge trade surplus with Canada and they would be wise to ensure any trade dealings with Canada are "absolutely fair and above board."

Celil made a court appearance last week in Urumqi, the capital of China's western Xinjiang region. But there was no Canadian diplomat present -- a violation of his rights as a Canadian citizen.

Chinese officials have insisted Celil is a Chinese citizen and, as a result, consular rules do not apply in this case.

Meanwhile, Celil's relatives say they believe he is being tortured, an allegation quickly dismissed by the Chinese.

Celil, a member of the Uighur minority group in Xinjiang, was born and raised in China.

Chinese authorities have long maintained that Uighur militants are leading a violent Islamic separatist movement.

Celil was arrested in China and tortured, but escaped from prison in 2000 and fled to Uzbekistan and Turkey before reaching Canada, where he was given citizenship.

Harper was responding to comments from He Yafei, which he made in an interview with the Globe and Mail.

"The economic relationship goes hand in hand with the political relationship," he said.

"I cannot say Canada is squandering (the relationship) now, but in practical terms Canada is lagging behind in its relations with China."