Volkert van der Graaf, the man jailed for 18 years for murdering politician Pim Fortuyn, is appealing against the junior justice minister’s decision to prevent him from going on trial home visits ahead of his release next year.

On Friday, junior justice minister Fred Teeven refused to grant Van der Graaf early leave, saying there would be a serious risk of public disorder and Van der Graaf and his family could also be under threat.

The security Van der Graaf needs would prevent him integrating back into society, the minister said. Pre-release leave is aimed at easing people back into normal life.

Van der Graaf, a militant animal rights activist, shot Fortuyn dead in a car park in Hilversum shortly before the 2003 general election. Fortuyn’s LPF party was riding high in the polls at the time.

Van der Graaf will be eligible for early release in May 2014 if he completes two-thirds of his sentence without incident.