Amsterdam - Two Dutch journalists posing as workers have exposed security flaws at the Dutch royal palace when they gained entry to the palace compound last month, National Coordinator for Counter Terrorism director Erik Akerboom acknowledged Monday.

Akerboom was reacting to a television programme aired by SBS broadcasting Sunday evening in which undercover journalists Alberto Stegeman and a colleague showed how they entered Noordeinde Palace in The Hague unhindered by posing as workers for a renovation company.

In the October 22 incident, the pair even brought a fake bomb in their car which the security staff of Queen Beatrix's work palace also did not check.

The two subsequently walked around freely at the Noordeinde compound, among others entering the horse stables.

Opposition parties Liberal VVD, left-liberal D'66 and the Socialist and Green parties said they were "shocked" and would request clarification from Interior Minister Guusje ter Horst and Defence Minister Eimert van Middelkoop (Defence).

Security measures to protect the royal family were stepped up after April 30, when a 38-year-old male drove his car into onlookers at the Queen's Day parade in the town of Apeldoorn, killing six and injuring 12.

The Queen and other royal family members were not injured. The man, who later died of his injuries, told a police officer he intended to hit the royal family. (dpa)