The move is just the latest in a long-running series of hints, offers and negotiations that have so far failed to convince the National Alliance and the United List – the two current partners of Kariņš' New Unity party – that a change in the coalition's composition is necessary.
Kariņš has been pushing – albeit not with any great sense of urgency so far – for the opposition Greens and Farmers Union (ZZS) and Progressives to be allowed into government to form a five-party coalition instead of the existing three-party model.
Speaking after talks with President Edgars Rinkēvičs, Kariņš appeared to slightly modify the offer, suggesting that two alternatives lie ahead in the absence of any agreement to expand the coalition. One is to continue working with the existing government model but with various ministerial changes and a greater dynamism, or alternatively to change partners completely and form a brand new government with ZZS and the Progressives.
"Both options are possible, mathematically the votes in the Saeima would add up in both options," said Kariņš.
How serious the threat is of ripping up the coalition model agreed less than a year ago remains to be seen – but both ZZS and the Progressives feel that they are owed payback for helping get Kariņš' former party colleague Rinkēvičs installed as Latvia's President. Neither the National Alliance nor the United List backed Rinkēvičs' candidacy.
On the other hand, Kariņš offered enticements as well as veiled threats to his current partners, with the attractive vacant position of Foreign Minister potentially going to the National Alliance's Rihards Kols.
A meeting of the current coalition is scheduled for Thursday from which only two outcomes are possible, according to the Prime Minister. If both partners say "Yes", there will be a ministerial shuffle and the government will continue work, Kariņš pointed out.
"If either of them does not agree, I will start the process of forming a completely different government with the Progressives and ZZS," said Kariņš.
He admited that such a government would not be an ideal option either, holding only a narrow majority in Saeima (it would have just 52 votes compared to the current 54 votes), but if there was a change of government, there would be "dynamism, there would be new winds".
"I am ready for both options," said the Prime Minister.
For his part Rinkēvičs indicated that he expects to see results before the end of the month.