Helena Guergis has stepped down from the Conservative cabinet and will sit outside the party caucus while the RCMP completes an investigation into her conduct, Prime Minister Stephen Harper said Friday.

Harper held a brief news conference Friday and confirmed that Guergis had just resigned from her position after "serious allegations" about her conduct were relayed to his office.

"Last night, my office became aware of serious allegations regarding the conduct of the Honourable Helena Guergis. These allegations relate to the conduct of Ms. Guergis and do not involve any other minister, MP, senator or federal government employee," Harper said.

"I've referred the allegations to the Conflict of Interest and Ethics Commissioner and to the RCMP. Under the circumstances, I will not comment on them further."

The prime minister said Guergis offered her resignation and he accepted it.

"Pending a resolution she will sit outside the Conservative party caucus," he said.

Harper said Public Works Minister Rona Ambrose will immediately take over the portfolio Guergis vacated.

While Harper didn't elaborate on the nature of the RCMP investigation, CTV News has learned that the Mounties will probe allegations that Guergis' husband, former MP Rahim Jaffer, used his wife's office to conduct commercial business.

Additionally, CTV Ottawa Bureau Chief Robert Fife reported late Friday that the RCMP will investigate allegations that Guergis accompanied her husband to business meetings.

Despite the buzz around Parliament Hill, a further allegation against Guergis is being kept a deeply guarded secret, Fife said.

"In fact, one of the allegations … no one will even talk about, because it's so sensitive," he said.

Still, Fife said that there are indications from some sources that Guergis may not be directly involved in the most serious allegations.

"Ms. Guergis herself has said that the allegations are baseless and unfounded," Fife said.

Liberal Leader Michael Ignatieff told reporters that the public should know more about the specific allegations made against the demoted junior cabinet minister.

And he suggested that the prime minister's about-face on the matter raised questions as well.

"Just 24 hours ago, the prime minister was saying he had confidence in this minister, and now 24 hours later -- boom, she's gone," Ignatieff said Friday, about a half-hour after Harper's announcement about Guergis' resignation. "It raises questions about the prime minister's judgment."

The announcement that the embattled MP has left the Tory cabinet, followed a tumultuous period that saw her personal finances and behavior called into question and her husband centered out in an unflattering report by a Toronto newspaper.

Minutes before Harper announced Guergis' departure from his cabinet, she sent out an email indicating that she had resigned from her position.

In the email, Guergis said she had been through "a very difficult time" over the past nine months.

"This morning, I tendered my resignation as Minister of State for Status of Women to the Prime Minister which he accepted," the email states. She goes on to say she has "made mistakes for which I have apologized," including an incident at an airport in Charlottetown in which she made disparaging remarks while going through security.

"I want the people of P.E.I to know that when I spoke emotionally I was speaking about the airport as I would never insult my father's birthplace. I apologize again. I have worked hard for Canadian women and I am proud of my record of my accomplishments on their behalf," she said in the email.

Guergis said she will continue on as the MP for Simcoe-Grey.

Mounting problems

The change comes a day after a controversial Toronto Star newspaper report suggested that a business associate of Guergis' husband -- the one-time Edmonton-Strathcona MP Jaffer -- bragged in an email that the former parliamentarian had "opened up the Prime Minister's Office to us," during a meeting in which the former MP and a group of businessmen discussed means of obtaining government funds for business projects.

In response, the Prime Minister's Office said Thursday that the claim was "absurd" and said neither Jaffer nor his associates had any influence within the government.

The report came after some difficult months for the well-known political couple.

In recent months, the 38-year-old Jaffer pleaded guilty to careless driving in relation to an arrest last September after being stopped in his car in Palgrave, Ont., north of Toronto. He was initially charged with drunk driving and cocaine possession, but those charges were dropped.

The Star reported that the arrest came the night Jaffer was driving home from the meeting where he allegedly was talking to the business associates about his connections to the Conservative government.

Guergis has also caught the attention of the media several times in recent months.

In recent weeks, a Liberal MP asked the ethics commissioner to examine an $880,880 mortgage Guergis was recently approved for, which she used to purchase a house in an upscale Ottawa neighbourhood.

That followed a February incident in which Guergis allegedly threw a temper tantrum at the Charlottetown airport. After that it was revealed that some of her staff members wrote flattering letters to newspapers about her record as an elected official, though they did not let the publications know that they worked for Guergis.