The change of heart may lead to a split in the party but could help the conservative HDZ to continue ruling without a second snap election in less than a year.
In an unexpected political turnaround, the Croatian liberals decided on Wednesday to join a coalition with the ruling conservatives, just a day after saying they would not.
"In talks with the [ruling] HDZ party, we will require running three ministries," said Predrag Stromar, a senior official of the Croatian People's Party (HNS), after a party council meeting comprising more than 100 members overturned the previous the decision to shun the coalition.
On Tuesday, HNS leader Ivan Vrdoljak resigned after the party's presidency rejected his proposal to enter the HDZ-led government headed by Prime Minister Andrej Plenkovic.
In April, Plenkovic fired four ministers from the previous junior coalition partner, the centre-right Most ("Bridge") party, as Most supported the opposition in a no-confidence motion against Finance Minister Zdravko Maric, which he survived by one vote.
The HNS has nine members of parliament, and it is likely that some of them will not vote for the new majority. Plenkovic, who is also the HDZ leader, must get support from several other deputies, some of them independent, and representatives of national minorities to clinch a new parliamentary backing.
Plenkovic must propose four new ministers to parliament soon to replace those from Most and reshuffle his cabinet to accommodate ministers from the HNS. A vote on those appointments will be the ultimate test of whether he has secured enough parliamentary backing for his cabinet to stay on.
A new early election, after the one held last September also following a split between the HDZ and the Most, would harm the pace of economic reforms needed to improve the investment climate and meagre long-term growth prospects in one of the European Union's weakest economies.