BUCHAREST, Sept 28 (Reuters) - The Romanian government of Liberal Prime Minister Florin Citu will face a no confidence vote on Oct. 5 after three parliamentary parties including a former ruling coalition partner agreed to back just one of two rival motions. USR Plus, which quit the coalition this month, the opposition ultra-nationalist AUR and leftist Social Democrats (PSD) are far from natural allies, but together they could garner a slim majority that could topple the cabinet next week. If they manage to unseat Citu, then the president would need to nominate a new prime minister, which could be Citu again. However, he would need to secure new alliances or seek a minority government - potentially halting reforms to tackle the large budget and current account deficits and delaying recovery plans after the coronavirus pandemic, given the fragmented parliament and different factions within the parties. USR Plus do not oppose a centrist coalition but resigned from the cabinet after Citu fired its justice minister in a row over a regional development fund. It has said the coalition can only continue with a different prime minister. Meanwhile, the PSD, which had proposed a rival motion to that of USR Plus and AUR, said it wants to trigger an early election. It accuses the government of damaging living standards and of poor handling of the pandemic, with the country recording record daily infections on Tuesday amid one of the lowest EU vaccination rates. read more A snap election, triggered if parliament rejects two proposed cabinets within 60 days, looks unlikely as it has never happened before - with lawmakers traditionally finding a way forward, however fractious. Citu said his Liberal team would negotiate to keep the government"s majority to try to see off the threat. "We are waiting for our USR Plus partners to continue with this coalition," Citu told reporters, "but we will draw the line the moment they will vote for a motion against the government together with AUR and PSD." The Romanian leu was down 0.1% against the euro on the day and 1.7% overall this year, the region"s worst performer.