"If I don't run, I have to know that there is someone else who has the strength," Ms Sahlin said. "I have to force myself to think about who will take over. Otherwise this might end in disaster.''
"I am going to write a letter to the party and ask the members to reconsider their choice," she said. "If they can find someone better, they should elect him, or her."
Her comments came as prosecutors appeared likely to announce an official investigation into her repeated misuse of her government credit cards. Ms Sahlin's borrowing of taxpayer funds for private purchases, cash withdrawals, car rentals and family holidays are part of a mountain of press revelations about her unministerial handling of her private finances. She has been chased by bailiffs over late payments of private credit card debts, a tax debt, a late television-licence payment and 19 parking fines.
According to two opinion polls published on Saturday, a majority said Ms Sahlin was not fit to be prime minister. "I'm so sorry about the whole thing, I can hardly speak without crying," she said. "I have never, ever, stolen one single krona."
Mona Sahlin was what was known in the Swedish Labour movement as an "A- Child". Steeped in the Social Democratic institutions that helped make Sweden what it is today, she epitomised the new guard of realists who would take a tired party into the next century.
By her thirties, she had become the party leader's favourite, who could be trusted to dismantle the welfare state while speaking the language of the common man. That was until last week, when it was disclosed that she also had been up to things that her Prime Minister and mentor, Ingvar Carlsson, could not have imagined.
As the tabloid campaign of revelations has accelerated, Ms Sahlin has admitted her actions piecemeal, while insisting she had paid back every krona to the government. She now stands accused of being economical with the truth, but also of betraying the trust of Mr Carlsson, who had groomed her to take over when he steps down in March.
Ms Sahlin, 38, insists her transgressions were minor: "If you want a human being who is perfect in all respects, who has never ever paid a bill late, then you shouldn't be talking to me," has been a stock reply.
Already accused of demolishing the welfare state, Ms Sahlin is now seen as lowering moral standards. Mr Carlsson has "full political confidence" in her. But, as one opposition politician put it: "I don't think that Carlsson understands that people like that actually exist. I imagine his first reaction was that all credit-card companies should be banned."
Opposition politicians say Ms Sahlin, widely seen as an intellectually lightweight populist, was a disaster waiting to happen; that her rise was symptomatic of the party's lack of talent. She joined when mostgifted young Swedes spurned the grey colossus of Social Democracy in favour of the right or far left.
Her job was to cut into unaffordable welfare structures while meeting the cameras with an unswerving gaze and to keep a pro-European course in a party plagued by Europhobia, less than a year after Sweden's EU entry. Her supposed youth appeal includes almost punk-style hair and a penchant for High Street fashion. Her salary is 660,000 kroner (pounds 60,000) a year.
She lives with her husbandand four children in a typical terrace in Stockholm's southern suburbs. Many Swedes do not understand how she could have run low on cash, and suspect bigger skeletons in the financial closet. Speculation now focuses on whether the Co-ordination Minister, Jan Nygren, or the Finance Minister, Goranm Persson, will replace her.Reuse content