By Alastair Macdonald

BRUSSELS (Reuters) – Belgian Prime Minister Charles Michel said his government would continue as a minority administration after the biggest party in his coalition quit on Saturday in a row over signing the U.N. migration compact.

Michel, a French-speaking liberal, said he “took note” of the departure of the Flemish N-VA from the four-party coalition formed in 2014 and would reshuffle posts — a particularly complex task in bilingual Belgium, as French- and Dutch-speakers must by law have an equal number of ministerial posts.

With a federal election due anyway in May, many observers expect no immediate change to that electoral calendar.

In a move critics have described as an opening shot in that election campaign, the right-wing N-VA, which is the biggest party in parliament, said it was pulling its ministers from the coalition after Michel refused its demand that he rescind a plan to sign the U.N. migration compact in Marrakesh on Monday.

Michel had secured a large parliamentary majority last week in favour of maintaining Belgium’s support of the United Nations text, which since it was agreed by all U.N. states bar the United States in July has run into criticism from European politicians who say it could increase immigration to Europe.

The N-VA faces electoral losses in its Dutch-speaking region to the harder-right, anti-immigration Vlaams Belang. Its leader Bart De Wever, the mayor of Belgium’s second city Antwerp, had issued Michel an ultimatum that it would quit the government if he signed the non-binding U.N. declaration.

A crisis cabinet meeting on Saturday night was cut short when two N-VA ministers, Interior Minister Jan Jambon and Migration Minister Theo Francken, walked out.

Michel said he would replace N-VA ministers with lower-ranked state secretaries and maintain a minority coalition involving his French-speaking liberal MR and two Flemish parties, the centre-right CD&V and Open VLD.

At least six EU states — mostly in formerly Communist eastern Europe — have already shunned the accord to regulate the treatment of migrants worldwide, a sign of how the bloc has turned increasingly restrictive on accepting refugees and migrants alike since a 2015 spike in arrivals.

(Reporting by Alastair Macdonald; Editing by Daniel Wallis)