A new poll of polls shows support for the anti-immigration PVV has dropped steadily over the past month while backing for the ruling right-wing Liberal VVD is rising, broadcaster Nos said on Wednesday.

The PVV remains the biggest party in the poll – which is based on four separate opinion polls – but its support has gone down from between 22.6% and 26% to 21.6% and 23.3%. By contrast, support for the VVD has risen to between 16% and 18.5%, a rise of around three percentage points.

Political scientist Tom Louwerse said there are two likely reasons for the changes. Firstly, prime minister Mark Rutte’s recent Correspondents’ Dinner speech to journalists had delivered good publicity, he said. And secondly, the refugee theme, which has boosted the PVV, is no longer considered ‘breaking news’.

The Socialists, Christian Democrats and Liberal democratic D66 are all around the 9% to 12% support mark.

Dutch opinion polls are based on the number of seats in the 150 seat lower house of parliament. The poll of polls gives the PVV between 31 and 35 seats and the VVD 24 to 28.

The next general election is expected to take place in around a year’s time.