Amsterdam  - Queen Beatrix of the Netherlands was due to open parliament in The Hague amid tight security Tuesday in what will be the first public appearance for the royal family since a failed attack on them in late April.

Police have closed the city centre to traffic for the traditional ceremony but the public will be allowed to line the route the queen will take in a 15-minute carriage ride from the Noordeinde Palace to parliament.

On April 30, a man tried to attack the royal family during Queens Day celebrations by driving his car into a large crowd in Apeldoorn in the eastern of the country. Failing to hit the open-top bus carrying the entire royal family, he killed eight bystanders before ploughing into a monument. The attacker, Karst Tates, whom police said had acted alone, died of his injuries the next day.

Additional security staff would accompany the golden carriage carrying Beatrix, her son Crown Prince Willem-Alexander and his wife Maxima. The family is due would appear on the palace balcony before the tour starts at 1 pm (1100 GMT).

The 19th century uniforms police traditionally wear on the occasion has also been replaced by contemporary attire, "to ensure police can act quickly and have their arms at hand", a police spokesperson said. (dpa)