The parties, which have 50 votes in the 100-seat Latvian chamber among them, have also invited the KPV LV party to join the new government; they will wait until January 3.
"We have come to a decision this morning that we're open and we await KPV LV to join the new government. But should they decide differently, the four parties will ask the government be put to vote in any case. I do not consider this to be an ultimatum," said New Conservative MP Juta Strīķe.
She did not offer a reply as to where they'd find the support that would be lacking if KPV LV do not join. Earlier KPV LV decided to forgo joining the government, as their leader Aldis Gobzems' candidacy for Interior Minister was ruled out by the other parties.
This follows protracted coalition talks which have been fruitless since the October 6 election.
Most recently, on December 24, maverick MP Artuss Kaimiņš (KPV LV) - who was on a large degree responsible for his party's successful election run - made things murky by offering to set up a coalition without Gobzems as Interior Minister and without any former ministers in the new government.
This followed other apparent splits within the KPV LV party; most involved Kaimiņš adopting different positions from Gobzems, which may suggest a falling-out inside party lines.
Another potential scenario to secure a majority would be including the Greens and Farmers Union (ZZS), however the New Conservatives have repeatedly insisted they would not join a coalition with ZZS.
After a meeting with President Raimonds Vējonis, KPV LV co-chairman Atis Zakatistovs said that there is a possibility of compromise in regards to the formation of the new government.
He did not specify whether the party would recall its nomination of Gobzems for Interior Minister, saying simply "maybe, or maybe not" when probed whether KPV LV would accept Gobzems to take up a different ministry.