Three parties are running almost neck-and-neck in the Dutch election race, according to the latest opinion poll by I&O Research.

Nieuw Sociaal Contract (NSC), the party founded by former Christian Democrat MP Pieter Omtzigt, has seen its lead slip to less than 0.5% of the vote over the left-wing alliance of Labour (PvdA) and GroenLinks.

The right-wing Liberal party (VVD), led by justice minister Dilan Yesilgöz, has closed the gap in third place, running 1.5% or three seats behind NSC, with just over nine weeks remaining until voters go to the polls.

The VVD appear to have been the main winners from the collapse of a smaller right-wing party, JA21, two of whose MPs defected earlier this month to the farmers’ party BBB. JA21 has gone from three virtual seats to one.

The poll was taken before the conflict within the animal rights party PvdD broke through the surface, which saw party leader Esther Ouwehand deselected and then reinstated after the party’s management board resigned. According to I&O’s research PvdA/GL is best placed to pick up any voters who switch from the PvdD.

On I&O’s projection NSC would win 28 of the 150 seats, three fewer than in the previous poll on August 24, after taking 18% of the vote. PvdA/GL would take 27 seats (17.6%) with the VVD on 25 (16.5%).

The next largest parties are the anti-Islam PVV led by Geert Wilders on 14 seats (9.1%), the BBB with 14 seats (9%), the PvdD with 7 seats (4.9%) and coalition party D66 on 6 seats (4.1%).

Coalition halved

The four parties in the coalition – VVD, D66, the Christian Democrats (CDA) and ChristenUnie – would win just 39 seats on I&O’s projection, half the number they won in 2021.

The poll also shows just one in six voters have made up their minds about who to vote for, with 59% undecided but leaning towards one party and 24% defining themselves as “floating voters” with no clear preference.

Housing is seen as the most important campaign issue by voters, with 41% seeing it as significant. Poverty, healthcare and immigration were all cited by between 33% and 35%.

Omtzigt was seen as the best candidate for prime minister, even though he has insisted he would reject the job to stay in parliament. More than half (54%) of all voters regarded him as a reliable leader, followed by Yesilgöz on 48%.

Frans Timmermans, the leader of the PvdA/GroenLinks combination, is popular among left-wing voters but only three in 10 of all voters backed him and just 21% believe he “understands ordinary people”, compared to 71% for Omtzigt and 39% for Yesilgöz.