The Italian senate has opted to summon the prime minister, Giuseppe Conte, to parliament on 20 August to respond to the crisis facing his government after one of the coalition’s members withdrew its support. When Conte returns, he could face a vote of no confidence or may choose to resign.

Matteo Salvini’s far-right League party had pushed for the vote to be held on Wednesday as it desperately seeks to end its fractious coalition with the anti-establishment Five Star Movement (M5S) and bring about snap elections, but was opposed on Tuesday night by senators from the M5S, the centre-left Democratic party (PD) and other parties.

As insults were traded between the opposing groups, Salvini said he would accept a proposal by the M5S leader, Luigi Di Maio, to cut the number of parliamentarians from 951 to 605 if it was swiftly followed by new elections.

If Conte loses the 20 August confidence vote, the government would have to be dissolved by the president, Sergio Mattarella, and elections held within 45 to 70 days. Mattarella could also choose to install a technical government.

Salvini, who is eager to capitalise on the League’s flourishing popularity, is fearing a potential alliance between factions from the PD and M5S who could attempt to carve out a caretaker government in order to pass the 2020 budget, with a the view of delaying elections until early next year. The move is being led by the former prime minister Matteo Renzi but has been rejected by the PD leader, Nicola Zingaretti, and Di Maio.

Most are counting on Mattarella, who is currently on holiday on an island off Sardinia, to clear up the ambiguity. He is reportedly unlikely to support a M5S-PD tie-up.

A survey on voting intentions on Monday put the League at 38%, the PD at 23% and M5S at 16.5%. Brothers of Italy, a party with neofascist lineage and a potential government partner for the League, is at 8.0% while Silvio Berlusconi’s Forza Italia, another League ally, is at 6.5%.