GRAND FALLS, N.B. - The physical and mental health of a New Brunswick farmer who's been stuck in a Lebanese jail for more than eight months has deteriorated further, his sister said after a recent visit to his jail cell.

Harmien Dionne recently spent two weeks in Beirut with her brother, Henk Tepper, after he called and pleaded with her to come to the Middle Eastern country.

Dionne said the potato farmer had lost 20 pounds, seemed mentally shaken and told her he didn't know how much more he could take of the imprisonment.

"It's not the same person who I saw in the month of May -- now I could see by looking in his eyes that there's a lot of pain, lots of frustration," she said from her home in Grand Falls earlier this week.

"He said, 'Harmien, I don't know how much longer I can go."'

Tepper was detained in Beirut last March under an international arrest warrant over allegations that potatoes he exported to Algeria in 2007 were rotten and that he forged trade documents.

His lawyer denies the allegations and says he's frustrated the Canadian government hasn't intervened to try to secure his release.

"They just haven't been involved in the process," Jim Mockler said Friday.

"It seems like the waiting just drags on and on and on. I'm beyond frustrated. He's desperate and he wants to be home before Christmas."

Canadian government officials have said they can check on Tepper in jail, but can't intervene because it is a legal matter.

But Dionne said her brother only sees an official from the Canadian consulate every month or two and hasn't received adequate health care.

She said she saw him a couple of times a day two weeks ago and became increasingly distressed about his mental and physical health.

She said Tepper, who has two teenage daughters home in New Brunswick, spends his days in a small cell with no natural light, is not allowed outside and can only make one phone call a week.

"The only thing that's on his head is, 'How am I going to get home? How am I going to get back to my family?"' she said.

Dionne said she has appealed to several federal government departments and has written to Prime Minister Stephen Harper, but hasn't received any indication they are trying to free her brother.