Tensions within the alliance led by the nationalist Law and Justice (PiS) party came into the open after junior partners did not support the measures, which passed in parliament with opposition support.
The dispute over changes to animal rights laws, which are seen as an appeal to younger voters, halted talks on overhauling ministries and threatened deeper problems for the coalition.
The measures, which would ban fur farming and curb the ritual slaughter of animals, were opposed by all lawmakers from the ultra-conservative United Poland party. Most lawmakers from the other junior alliance partner, Accord, abstained.
PiS lawmaker and Agriculture Minister Jan Krzysztof Ardanowski, who had openly criticised the bill, voted against it.
Opponents of the bill within the ruling alliance said it would alienate voters in PiS’s rural heartlands and hurt farmers.
Poland produces millions of furs a year, and the sector employs about 50,000 people. The country is also one of Europe’s biggest exporters of halal and kosher meat, with 2017 shipments of more than 70,000 tonnes.
Talks had been underway between PiS, United Poland and Accord over plans to reduce the number of ministries, potentially concentrating power in the hands of PiS.
“Negotiations.... have been suspended due to the situation we have in the Sejm,” or parliament, PiS lawmaker and Deputy Parliament Speaker Ryszard Terlecki said before the vote.
Asked about ruling as a minority government, Terlecki said this would not be possible.
“If that happens, we’ll go to elections. Alone, of course.”
In 2007 PiS decided to go for early elections and lost power, making the party well aware of the risks of such a move. Reporting by Marcin Goclowski, Alan Charlish, Anna Koper and Alicja Ptak; Editing by Andrew Cawthorne, Alexandra Hudson and William Mallard