VANCOUVER - The actor best known for his portrayal of Russian crew member Pavel Chekov on the original "Star Trek" television series made an impassioned plea Wednesday for people crowded into Vancouver for the Winter Olympics to keep an eye out for his missing son.

Walter Koenig said his son Andrew -- himself an actor who played Richard "Boner" Stabone in the 1980s sitcom "Growing Pains" -- suffers from depression.

He said Andrews had been off his medication when he vanished nearly two weeks ago while visiting Vancouver.

"I implore, I beseech, I humbly request that even during this extraordinary time, when you have the Olympics here and there's so much going on, if the population can take one more step and try to be aware that we have a son, Andrew Koenig, who is presently missing, whose state of emotional health may not be very good," Koenig told a news conference in Vancouver, his wife Judith at his side.

"Just look out for him."

Police say 41-year-old Andrew Koenig was last seen in Vancouver on Feb. 14. He was due back in Los Angeles two days later but never showed up.

Since then, police have canvassed the man's friends and searched Vancouver's sprawling Stanley Park, one of his favourite spots in the city, but so far haven't turned up anything. His cellphone hasn't been used since Feb. 16, and he last accessed his bank account a few days before that.

Koenig's parents said their son has battled depression his entire life and before he vanished, he gave away and sold some of his possessions and even cleared out his apartment in Los Angeles.

He last spoke with his mother a few days before he disappeared, and she said he sounded "up but detached" during their conversation. Walter Koenig received a letter from his son a few days later, although he didn't reveal what exactly was in the letter.

Walter Koenig said he is especially concerned his son may harm himself.

"I think it's almost impossible not to explore that as one of the options," he said. "Since I am of a psychological orientation that goes there first, it's certainly something that has been torturing me."

The Koenigs addressed their son directly, pleading for him to contact his family.

"To my son directly: We just want to know that you're OK," said Walter Koenig, his voice breaking. "If it means you want to stay here, you want to change your life and stay here and find peace and happiness here, that's OK. You don't have to come back, just let us know."

Koenig said his son first came to Vancouver while filming an episode for the 1980s television show "21 Jump Street" and fell in love with the city, staying for another three years. During that time, he had little contact with his parents.

He said his son's depression has always been a lifelong concern, but it hasn't stopped him from pursuing a career first as an actor and more recently as a video producer for Internet films and podcasts.

"It has not prevented him from being a participant in his community, in his industry, it hasn't prevented him from being an activist dealing with environmental situations. This is a committed human being, a very good person whom we are both very proud of."

Andrew Koenig's other television credits include "Star Trek: Deep Space Nine," "G.I. Joe" and "My Two Dads," while he has appeared in several movies including "NonSeNse," "InAlienable" and "The Theory of Everything."

His father also noted his son's activism on environmental issues and, more recently, for the plight of refugees from Myanmar, formerly known as Burma.

He was arrested in 2008 during the Rose Bowl parade in California, while protesting China's support for the country's military junta government.