ROME: Italy's President Sergio Mattarella wants parliament to draft a new electoral law before any ballot is held, a source close to the president said on Tuesday, a move likely to delay any vote after Prime Minister Matteo Renzi resigns. Renzi said he would step down after losing a referendum on constitutional reform on Sunday, but Mattarella asked him to stay on until parliament passes the 2017 budget, a vote scheduled for Wednesday.. The next parliamentary election is not scheduled until 2018 but on Tuesday there was growing consensus among party leaders for it to be held a year earlier. Interior Minister Angelino Alfano said the vote should be held in February. Senior members of Renzi's Democratic Party (PD) will meet on Wednesday to discuss the referendum defeat and the party's future strategy. On the eve of the meeting, two PD sources said the party would support a government of national unity, which would have to include parties that had been in opposition. If such a government is not possible, then the PD wants an early election. The president wants a new law to follow a Constitutional Court ruling on the legitimacy of the lower house voting law adopted last year, the source said, which is not due before a Jan. 24 hearing. Another voting law has been in place for the Senate since 2014. Voting with two different laws is widely seen as a recipe for continued political instability in a country that has seen 63 governments in 70 years. ELECTION IN SPRING? Infrastructure Minister Graziano Delrio, a PD member and close ally of Renzi's, said on television on Tuesday the best solution would be for an interim government to be put in place to quickly change the electoral law so an election could be held 'in the spring'. The final decision on when to dissolve parliament rests with Mattarella, and his conditions mean it would be virtually impossible to hold an election before the end of March. 'I forecast there will be the will to go to elections in February,' Alfano, head of a small centre-right party that is part of Renzi's coalition, told Corriere della Sera daily on Tuesday, after discussing the issue with Renzi. The two largest opposition parties, the eurosceptic, anti-establishment 5-Star Movement and the right-wing Northern League, are both pushing hard for an election. But it will take time for parties to hammer out a deal on a new voting system, and, after parliament is dissolved, 45 days must pass to allow time for campaigning ahead of the vote. Renzi is still leader of the PD, which has the largest number of parliamentarians, so it is unlikely any new government could be formed without his backing.