There are now 17 different parties and splinter groups in the 150-seat lower house of parliament following the decision by Labour MP Jacques Monasch to quit the party because of differences over the leadership election.

In the March 2012 general election, 12 different parties won seats, but eight MPs have now left the party they were elected to serve.

By law, they are entitled to remain in parliament and home affairs minister Ronald Plasterk has rejected calls to change the constitution to force them to stand down.

Monasch’s decision to quit means the VVD Labour coalition, which had 79 seats after the election, no longer has a majority in the lower house.

However, both party leaders – Diederik Samsom and Mark Rutte – have said this is unlikely to be an issue in the run up to the next general election.

Meanwhile, the PvdA says around 1,000 people have joined the party to take part in the vote for a new leader. Samsom is being challenged by social affairs minister Lodewijk Asscher.