* Campaign official says 'page has turned'
* Fillon tries to lure back centrists
* New poll again shows Fillon knocked out in round one (Adds Fillon, UDI meeting, pollster, quotes)
By Sophie Louet and Mourad Guichard
PARIS/ORLEANS, March 7 (Reuters) - France's Francois Fillon sought to put his presidential campaign back on track on Tuesday after a rebellion against his candidacy fizzled out, but the reluctance of key allies highlighted the difficulties he faces in rallying his camp behind him.
Fillon had been favoured to win the presidency until reports in January prompted a judicial probe over whether he used public cash to pay his wife for work she did not do, leading to a sharp drop in polls and an exodus of campaign staff.
The 63-year-old called for his much-divided camp to get over six weeks of doubts and criticism over the financial scandal, in which he denies any wrongdoing.
"I'm now calling for all of us to rally together, to be mobilised, to take action! I'm calling all the components of my political family to get their acts together and forge ahead for France!" he told an evening rally in the central France city of Orleans.
His backers took to the airwaves to say a page had been turned after, on Monday, former prime minister Alain Juppe decided not to challenge him and his conservative The Republicans confirmed he was their candidate.
But after delivering a scathing critique of Fillon on Monday at the same time he was ruling himself out as a replacement, Juppe turned down a proposal for a meeting with him and former president Nicolas Sarkozy, which Fillon's camp had planned as a show of unity, party sources said.
The smaller centrist UDI party, which has been so split on how to handle the Fillon case that officials feared the party could implode, on Tuesday decided to reserve judgment on backing him.
After the UDI suspended their participation in Fillon's campaign last week, its executive committee said on Tuesday evening that they backed Fillon's manifesto and were still keen on an agreed deal for the June parliamentary ballot that follows the April-May presidential elections.
But they added that they wanted to see Fillon take concrete steps to bridge divisions before rallying back behind him for the presidential races.
As in all his recent rallies, a small group of left-wing activists banged pots and pans near Fillon's Orleans rally.
The scandal looked set to keep dogging him. The weekly Le Canard Enchaine, which first reported on the allegations that Fillon's wife was paid for ghost jobs, wrote in its latest edition that investigators are now also looking into an undeclared 50,000-euro loan Fillon received from Marc Ladreit de Lacharrière, a businessman who employed Fillon's wife.
Fillon's lawyer told Le Canard the loan was fully reimbursed. In 2010, Ladreit de Lacharrière received France's prestigious Legion d'Honneur award, after a recommendation from Fillon.
Fillon now faces the prospect of being knocked out in the first round on April 23, leaving centrist Emmanuel Macron and far-right candidate Marine Le Pen to contest a run-off two weeks later.
Investors have been unsettled by the possibility of a win for Le Pen, who wants to take France out of the euro zone.
Le Pen, bidding to match the anti-establishment shocks of Donald Trump's U.S. presidential victory and Britain's vote to leave the European Union last year, is tipped in almost all polls to win the first round of the election.
But they universally show her losing the head-to-head run-off to Macron, a former economy minister, or to Fillon, were he to make it that far.
Key members of The Republicans party, who thrashed out the deal to rally behind Fillon on Monday, secured a pledge that he would temper his attacks on the judiciary and media, sources close to the party told Reuters.
Senate leader Gerard Larcher, one of the group of right-wing politicians behind Monday's pro-Fillon announcement, called for unity, saying failure would open the doors of power to Le Pen.
"I cannot resign myself to the idea of a second round where it's Le Pen versus Macron," he said.
Fillon has upset some members of his party and the UDI by complaining that the investigation amounted to a "political assassination" by the justice system and the media. Juppe said such talk had brought Fillon's campaign to a dead end.
"Things are very complicated for the Right," said Ifop pollsters' Jerome Fourquet. "Some voters and officials might come back ... but it is an illusion to think the whole (political) family will unite behind him."
(Additional reporting by Brian Love and Chine Labbe; Writing by Ingrid Melander and Brian Love; Editing by Jonathan Oatis)