"She has crossed all the boundaries that were there to cross," said Kučinskis.
Following the vote, said Kučinskis, there's no reason to think that Grigule's interests are the same of the Latvian government.
The Greens and Farmers Union is to meet their party mate Grigule and inquire as to her vote.
The party board is prepared to have Grigule leave, said Kučinskis.
Last week the European Parliament voted on the EP resolution on combating Russian propaganda.
Five Latvian MEPs voted for the resolution while three voted against: pro-Kremlin politician Tatjana Zdanoka, Andrejs Mamikins of the opposition Harmony party (which has a cooperation agreement with Vladimir Putin's United Russia party) and Iveta Grigule.
PM Māris Kučinskis distanced himself and his government from the vote quickly.