The proposed merger between left-wing parties GroenLinks and PvdA may happen sooner rather than later, the parties told their members in an email on Thursday.

The parties suggest bringing forward the decision by a year and taking a vote on the principle at the joint party conference in June.

“If the members say yes then we will forge ahead with a new movement which includes both parties. We can then focus our energy on the policies because that is what this country needs. We feel an enormous urgency to take this step,” PvdA party chairwoman Esther-Mirjam Sent told broadcaster NOS.

The vote would start the process of establishing party statutes and putting together a manifesto, taking the official founding of the party to 2026, which also marks the PvdA’s 80th birthday.

According to Sent and GroenLinks chairwoman Katinka Eikelenboom, bringing the decision forward is a reaction to an increasingly strong call from party members.

“We feel it’s an accumulation of both the instability and the political colour of this cabinet and the international instability,” Eikelenboom said. The membership of both parties has been growing, and the main thing is to be “as strong as possible as quickly as possible to present the voters with an alternative,” she said.

The two parties worked together in the 2023 elections and the alliance won 24 seats, making it the second biggest party in parliament. It has since then inched up in the polls. Members are expected to vote overwhelmingly in favour of the new party, which has yet to be named.

Not all members support the merger. A group comprised of former PvdA leader Ad Melkert and former chairs Gerdi Verbeet and Hans Spekman say they fear the party would set aside traditional social democratic values and become a party for the well-educated.