Announcing the news to reporters, head of the PS deputy group Jani Möderndorfer said the interim speaker would be asked to call a session at which both votes would be taken on Wednesday. He said the purpose of the no-confidence vote was to get a new government and to "end the agony", rather than get a "dummy PM".

The motion was filed after Möderndorfer and Bratušek met deputy groups of the Citizens' List (DL), Social Democrats (SD) and the Pensioners' Party (DeSUS) in the morning. The parties established "there is a basis to take a step forward", Möderndorfer said.

The move comes after weeks of negotiations between the opposition and the parties that have left the ruling coalition after PM Janša failed to resign in the wake of a damning report issued by the Commission for the Prevention of Corruption in January, which also compromised PS leader and Ljubljana Mayor Zoran Janković.

Slovenia "has found itself in the worst political crisis since independence", Möderndorfer said, adding that the PS as the biggest parliamentary faction decided to assume the responsibility to bring "this agony to an end".

He said the purpose of the vote was to get a government that would pull Slovenia out of crisis and "end the agony of Janez Janša and this government", which is "blocking the country".

Möderndorfer said Bratušek was "more than competent to run the executive branch of government". "She will perform her duties responsibly and by seeking a broader consensus among different political parties."

He said Bratušek proposed to the prospective coalition partners in the government they form to seek a confidence vote at the National Assembly a year after appointment.

If appointed, Bratušek would become Slovenia's first ever woman PM. Before joining the PS in late 2011, she had served as a senior official at the Finance Ministry under different governments.

The nomination of Veber for speaker of parliament is the product of talks on the no-confidence motion, according to Veber. The practice so far has been for the post of the speaker of the National Assembly to be given to the second largest coalition partner.

"Our interest in this phase is that we tackle the problem of the National Assembly's operation as soon as possible," said Veber, SD deputy group leader. The post of the speaker has been vacated by DL leader Gregor Virant after his party quit the ruling coalition in January.

The first reaction of Janša's Democrats (SDS) was that the no-confidence vote was an attempt to block the implementation of the legislation on the sovereign holding and bad bank, which they say jeopardises key measures aimed at protecting Slovenia's sovereignty.

The People's Party (SLS), who will withdraw from the government on 4 March, will consider their support for the no-confidence vote in view of whether it makes a step towards an early election, SLS vice president Franc Bogovič said.

The coalition New Slovenia (NSi) expressed doubt that prospective new coalition partners would be able to agree on a programme of the potential new government considering the only thing they have in common is opposition to the Janša government.

NSi deputy group leader Matej Tonin noted that at least two parties of the potential new coalition had diverging views on economic policies, in particular the sovereign holding and the bad bank.

Tonin recalled DL leader Gregor Virant's pledge that the Citizens' List would remain the defender of the economic policies of the Janša government and former Finance Minister Janez Šušteršič.