French presidential candidate Francois Fillon has taken back a promise to quit the race if placed under formal investigation.
Mr Fillon's campaign has been dogged by claims, which he denies, that his wife and two of his children were paid for non-existent parliamentary work.
While an initial investigation is already under way, a decision on a more formal probe has yet to be made.
"I am the candidate and I will continue until victory," he said.
"The closer we get to the date of the election, the more scandalous it would be to deny the Right and the Centre of a candidate," he told Le Figaro, adding that he had hoped a decision would have been taken sooner.
The first round of the election will be held on 23 April, with the second round run-off between two candidates two weeks later.
On 26 January, he had told the TF1 channel that "the only thing that would prevent me from being a candidate is if my honour was tainted, if I was placed under examination".
While France's financial prosecutor decided to keep an initial investigation open on Thursday, the decision to launch a more formal probe would need to be taken by a magistrate. It could take months or years to reach that point.
Media reports say Mr Fillon's Welsh-born wife Penelope earned €831,400 (£710,000; $880,000) as her husband's parliamentary assistant between 1998 and 2012, and questioned how much work she had done.
It subsequently emerged that Mr Fillon had hired two of his children to act as lawyers, paying them €84,000 between 2005 and 2007 - when they were students.
In early February, he said that although what he had done was legal, French people no longer accepted the practice and that he had made a "mistake".
The controversy has hit Mr Fillon in the polls, with one new survey by Ifop for three French media outlets on Friday suggesting he is neck-and-neck with centrist candidate Emmanuel Macron.
But the poll places both behind the far-right's Marine Le Pen.
"Despite the prominence of 'PenelopeGate' in conversations in France, and the storm around his campaign, Francois Fillon has this week managed to stop the electoral haemorrhage, and even to progress a little," Ifop's analysis said.
Polls indicate Mr Fillon or Mr Macron would easily beat Ms Le Pen in the second round of the election in May.