A Belgian court denied parole to child killer Marc Dutroux, ruling he could not be freed with a security tag on his ankle as there was no prospect of him fitting back into society.

Dutroux, 56, was sentenced in 2004 to life in prison for kidnapping and raping six girls and killing four of them in the 1990s.

He has been in prison since his arrest in 1996 and became eligible this year to request early release with an electronic ankle band.

The court said that it considered whether Dutroux would be able to integrate into society, whether he would commit new crimes, whether he would seek contact with the victims and whether he showed remorse regarding his victims.

"The court analysed the first issue and came to the conclusion that there was evidence against. This gives the court the opportunity to immediately deny the request," Luc Hennaert, court president, told reporters after the hearing.

Neither Dutroux nor his lawyer attended the court session.

In Belgium, electronic ankle bands are often used to allow police to monitor a detainee's whereabouts outside prison and to alert them if the person moves beyond a permitted area.

The Dutroux case has deeply traumatised Belgium because of the horrific nature of the murders and because of perceived errors made during investigations.

Belgian police visited one of Dutroux's houses where two victims, both eight years old, were being held and failed to find them.

The two later starved to death in a makeshift dungeon.

Jean Lambrecks, the father of Eefje Lambrecks who was kidnapped and killed by Dutroux when she was 19 years old, told reporters outside the court he was satisfied with the ruling.

"I hope he will sit out his sentence completely," he said.

Dutroux, who can make another request for an ankle band in February 2014, will have to appear before a judge again in April to discuss a full conditional release.

His former wife and accomplice, Michelle Martin, was released from prison in July last year and sent to a convent after serving half of her term.