PARIS - Senior members of French conservative party the Republicans unanimously supported Francois Fillon's presidential bid, despite a deepening legal investigation into the allegation about his wife's fake job, Senate President Gerard Larcher said on Monday.

At an emergency meeting, "the political committee unanimously renewed its support and confidence to Francois Fillon," Larcher said after an emergency meeting to hammer out an alternative to end the party's crisis triggered by Fillon's scandal over allegation of public fund misuse.

"Fillon indicated that he would take initiatives to bring our values together. The Republicans are therefore gathered and determined around (him), " he added.

The party's leadership decision came after ex-foreign minister Alain Juppe who lost to Fillon in November primary, refused to be "a Plan B" to re-launch the conservatives' bid to snatch power on May 7.

Fillon, 63, has been under growing pressure to quit the presidential bid after being summoned by magistrates over the affair and could be placed under formal investigation.

"No one has the power to force me to withdraw...It is not the party that will decide. It's not regional presidents or former primary candidates who will make the decision for me," he told France 2 television on Sunday.

Portraying himself as an honest and morally irreproachable politician, Fillon previously said he would step down if he were put under formal investigation.

Once the favourite to unseat the Socialist Francois Hollande, the conservative presidential candidate 's campaign is still haunted by fake job scandal which had took the wind out of his sails.

An OpinionWay survey conducted between Feb 27 and March 3 showed Fillon losing momentum with 19 percent of voting intention, down two percentage points from a previous poll.

He will be knocked out in the first round in which Marine Le Pen, far right party leader and centrist Emmanuel Macron are set to collect the highest vote, allowing them to pass to the run-off, according to the poll released on Monday

On January 25, French satirical weekly Le Canard Enchaine reported that Fillon had paid his wife and two of his five children about one million euros (1.06 million U.S. dollars) for their jobs as parliamentary assistants. However, there was no evidence showed she had really worked, the report added.

Fillon has repeatedly denied wrongdoing. Meanwhile, he apologized for the ethical "error" he made in hiring his wife and their two children, a practice which he said was no longer acceptable according to public opinion. (1 euro = 1.06 US dollars)