Prime Minister Stephen Harper has intervened on behalf of Brenda Martin, a Canadian imprisoned in Mexico, just days after she made an impassioned, desperate plea to Harper to save her life.

Harper has phoned Mexican President Felipe Calderon to discuss the case and told him that Secretary of State for Multiculturalism and Canadian Identity Jason Kenney will be visiting Martin in Guadalajara.

Martin, a 51-year-old Ontario woman, has been awaiting trial in Mexico for two years, accused of taking part in a $60-million fraud scheme orchestrated by her former boss Alyn Waage.

She denies the claims and maintains her innocence, saying she was simply Waage's chef, and invested in his company believing him to be a legitimate businessman.

Harper's spokesperson refused to discuss the phone call with Calderon, although he did not deny that the conversation took place.

"In two years we have had over 100 contacts with Ms. Martin and continue to raise her case up to and including the president of Mexico," Dimitri Soudas told The Canadian Press.

Last weekend, Mexico sent a diplomatic note to Ottawa asking that Canadian officials refrain from interfering in its judicial system.

"The government of Mexico reiterates its interest in and commitment to seeing the case resolved through the proper legal channels, ever respectful of the autonomy and independence of the judicial branch of government," says the note, which was obtained by CP.

During an interview last week on CTV's Canada AM, an emotional Martin begged Harper to call Calderon and request her release, saying she "couldn't get through a day."

Martin was recently placed on suicide watch in the prison's hospital ward and her emotional state appears to have declined in recent months.

Former prime minister Paul Martin paid Martin a visit recently, as did Liberal MP Dan McTeague.

But Kenney and Ontario MP Rick Norlock will be the first Conservative MPs to visit Martin in prison. They are scheduled to leave today on the two-day visit, CP reports.

"They intend to check up on her health, let her know that officials at the highest level are focused on her case, and ensure that any immediate needs are being taken care of," one government source told CP.

"They also intend to continue the process of raising her case with Mexican officials to underscore how serious Canada takes it."

Foreign Affairs Minister Maxime Bernier said he raised the case in Washington on Monday with his Mexican counterpart, and was assured that lawyers will be able to speak with Mexico's deputy attorney general.

A statement from the Mexican embassy said the case would be "concluded shortly" and blamed defence lawyers for her lengthy stay in jail, saying they could have separated her case from those related to the larger fraud case, but failed to do so.

"In not doing so, she remained linked to them and included in the global file comprising 25,000 pages," said the embassy statement.

Martin is facing counts of money laundering and being part of a criminal conspiracy. She has consistently maintained her innocence and threatened to kill herself if she is not released.

On Monday, Debra Tileman, Martin's friend who has been advocating on her behalf, said diplomatic efforts had been ineffective and called on Harper to pick up the phone.

Tieleman has been in regular contact with Martin and has visited her. She said her friend was "mentally unstable, emotionally devastated" and weakened physically because of her stay in the Mexican jail.