By David Ljunggren
OTTAWA, Jan 15 (Reuters) - A senior member of Canada's ruling Liberal Party said on Thursday she might defect to the left-leaning New Democrats in what would be an embarrassing blow to new Prime Minister Paul Martin ahead of an election expected in May.
Sheila Copps, the most prominent figure on the party's left wing, says Martin's aides are trying to force her out of her parliamentary seat to make way for Transport Minister Tony Valeri -- who backs the fiscally conservative prime minister.
If Copps switched sides, it would boost the rising fortunes of the New Democratic Party (NDP). The Liberals have a big lead in opinion polls, but Martin aides admit NDP leader Jack Layton could threaten their hopes of a fourth consecutive parliamentary majority.
Copps, a former heritage minister who served for 10 years under Martin's predecessor Jean Chretien, said Layton had called her on Wednesday.
Asked by CBC radio whether she was considering a move to the NDP, she replied: "I'd like to be a voice in the Liberal Party. If that becomes so unfair as to be impossible, I'm not going to close off my options."
In a dig at Martin, a millionaire businessman, Copps said she was "leaving the door open to remaining a voice in Canada to fight for the little people because I think we need those voices. They can't all be snuffed out."
Layton has invited Liberals to join his party.
"I don't know what Sheila Copps will decide, but to Liberals who share Sheila's values... I say you belong with us," he told reporters.
"I think Paul Martin is taking this country down a very dangerous course...that involves mimicking (U.S. President) George Bush and his politics," he said. No one in Martin's office was immediately available for comment.
Copps is from the powerful central province of Ontario, source of 96 of the 170 seats that the Liberals hold in Canada's 301-seat parliament.
One of the reasons the Liberals won elections in 1993, 1997 and 2000 was vote-splitting between the two main right-wing parties, which last month ended a decade of rivalry by agreeing to unite to form the Conservative Party.
The aide to one senior cabinet minister said the Liberals could now lose support from both the right and left, with the worst-case scenario being a minority administration.
"The risk is that Ontarians who think Martin is taking the country too far to the right will vote for the NDP and those who are conservative will say 'Why should we vote Liberal when there is a united right-wing party'?" the aide said.