Timmermans, 62, was appointed to the top spot in the PvdA (Labour) and GroenLinks (GreenLeft) coalition after a ballot in which some 91% of more than 37,000 party members backed his candidacy.

“An overwhelming majority has agreed to have Timmermans as leader,” the PvdA-GroenLinks coalition said in a statement.

Timmermans stepped down after 10 years in Brussels.

“I want to become prime minister, because I think together we can do politics differently than it had been done in the past few years,” Timmermans told Dutch media last month.

Timmermans’ term as EU executive vice-president had been scheduled to end after next year’s European elections.

But the collapse of outgoing Liberal premier Mark Rutte’s coalition over asylum issues triggered snap elections to be held on Nov 22.

Timmermans, whose social-democrat PvdA won a surprise victory in 2019’s European parliamentary polls in the Netherlands, was previously in charge of the EU’s flagship “Green Deal” drive to bolster the environment.

The ecology-minded politician is seen as a heavyweight contender from the left for the position of Dutch prime minister, left open by the departure of long-time leader Rutte.

Rutte, the leader of the centre-right VVD party, stunned the Netherlands by announcing last month he was quitting politics after 13 years at the helm.

PvdA and Green-Left members voted last month to merge their parties to form a single left-wing bloc in the upcoming polls, which is expected to be dominated by climate and asylum-seeker issues.