Isamaa MP Mihhail Lotman has told newspaper Maaleht that he does not support the marriage referendum in its current form. He is one of several Isamaa Riigkogu members who are against the forthcoming referendum.
"I am not opposed to referendums in principle, but I cannot vote in favor of this issue," Lotman said in an interview with Maaleht, referring to the fact marriage is already defined in the Family Law.
Siim Kiisler, Viktoria Ladõnskaja-Kubits and Üllar Saaremäe have already said they will not vote in favor of the marriage referendum.
The governing coalition of the Center Party (25 members ), EKRE (19 members) and the Isamaa (12 members) has 56 votes in the Riigikogu and in order to carryout out the referendum a majority of MPs will need to vote in favour of a bill proposing it.
As four members of Isamaa have now said they will vote against it, the government's majority is shrinking.
Anti Poolamets (EKRE) has said if a vote is not held then the coalition will collapse.
The referendum will seek to add a definition of marriage as between a man and a woman to the Constitution. That marriage is already defined this way in Estonia's Famiy Law has not deterred EKRE, which is the party pushing for the vote.
Editor: Helen Wright