The six are accused of links to an Islamist terrorist group, the BBC reports. They are also charged with planning to attack Dutch politicians and government buildings, and possessing weapons.
Nine members of the terrorist group already have been jailed including the man, who is serving a life term for the killing Dutch film-maker Theo Van Gogh.
Prosecutors in the latest trial think the six suspects, including a woman, are linked to the same Hofstad group.
The anti-terror laws were tightened after the main suspect among the six, 20-year-old Samir Azzouz, a Dutch Moroccan man, was acquitted last year although the court ruled he had terrorist intent. He was re-arrested on suspicion of planning new attacks under the news laws, which allow suspects to be tried for attacks that security forces believe they are planning to carry out, the BBC reported.