By Allison Lampert and David Ljunggren

MONTREAL/OTTAWA (Reuters) - Canada did not make concessions to China to secure the return of a Canadian citizen who spent two years in jail and was convicted of spying, Foreign Minister Stephane Dion insisted on Friday.

Kevin Garratt, charged in January with spying and stealing state secrets, was convicted on Tuesday, released on bail and then deported to Canada on Thursday.

The unexpected release prompted speculation on what Ottawa might have offered China, which is seeking a free trade deal with Canada, more relaxed investment rules, and the extradition of what Beijing has said are corrupt officials.

"The prime minister ... would never do these types of things," Dion told a news conference when asked what concessions Canada had made.

Prime Minister Justin Trudeau, who has made improving relations with China a priority, had pressed Garratt's case while on an official visit to China this month.

"It's one less topic to discuss with the Chinese ... and we'll be able to focus on other issues," Dion said. Chinese Premier Li Keqiang is due in Canada next week on an official visit.

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

Asked whether Canada would be more prepared to consider China's requests for the return of officials, Dion replied, "No, we will do what is right in our relationship with China."

Gordon Houlden, a former Canadian diplomat with extensive Chinese experience who heads the University of Alberta's China Institute, said the two nations' judicial systems were so different that they could never seal an extradition treaty.

Garratt's family members declined to comment on his condition, saying in a statement that he was recovering in the Pacific province of British Columbia.

Garratt's release marked the end of a protracted campaign.

"We never fail to raise the difficult issues in any meeting, anywhere," a government official said on condition of anonymity.

In an e-mail, Garratt's Beijing-based lawyer James Zimmerman described the effort as "a constant, unrelenting process of lobbying various players in both governments to keep the discussions alive".

The head of the Canadian Security Intelligence Service (CSIS) spy agency went to Beijing in June to stress Garratt was not an agent, Zimmerman added. CSIS declined to comment.

(Reporting by Allison Lampert; Writing by David Ljunggren; Editing by James Dalgleish and Richard Chang)