TAIPEI (AFP) - Victims of a Taiwan water park explosion that killed 15 and injured hundreds urged prosecutors on Monday (Feb 1) to open a new inquiry into the accident, criticising the indictment of just one person.

The accident happened last June at the Formosa Fun Coast water park, when clouds of multicoloured corn starch sprayed on revellers at a "colour party" ignited after heat from stage lights triggered a blast that ripped through the crowd.

Nine people were under investigation over the disaster, including the chairman and president of the water park outside Taipei. The park had rented out its premises to an events company for the party.

Prosecutors last year indicted Lu Chung-chi, owner of Colour Play Asia, which organised the event, and cleared the others.

Nearly 200 victims and relatives of the dead rallied in Taipei to demand justice and some marched to the High Prosecutors' Office to push for a new investigation.

"It's unfair only Lu was charged but the more influential and richer businessmen were cleared. I am still going through an extremely painful rehabilitation process and I want justice," said Ms Chu Yu-chen.

Ms Chu, 25, underwent eight operations for burns to around 50 per cent of her body and has been on sick leave from her publishing company since the accident.

Ms Huang Ying-xin, a 19-year-old college student who attended the party with a dozen friends and was badly burnt on the legs, agreed.

"The water park must take responsiblity as the event was held on its facility. Prosecutors should not let them get away with it."

Ms Julie Wang, a spokesman for a victims' association, added that the government of New Taipei City, where the park is located, should also bear responsibility for allowing the park to illegally rent out its venue.

The event, which drew around 1,000 people - mostly aged between 18 and 25 years - turned into a nightmare when the inferno ripped through the crowd. Almost 500 partygoers were injured, more than 200 of them seriously.

A district court is expected to rule in the case of party organiser Lu in April. He was charged with negligence leading to death and injury and faces up to five years in prison.