SYDNEY (AFP) - Chairs were thrown and tables were stomped on as violence broke out at a international darts competition in Melbourne, with spectators describing chaotic scenes of people being body-slammed into furniture while others urinated on the floor.

Audience members at the Darts Invitational Challenge told local media the violence started when some people in the crowd, many in fancy dress, tried to build a pyramid out of chairs late on Saturday night.

Video footage posted on social media showed plastic chairs and some tables being thrown towards a growing pile of furniture in the midst of the audience.

"There were entire rows basically demolished, chairs being put on piles and tables started getting involved," witness Andrew Portbury told the Australian Broadcasting Corporation.

"People were diving on top of the tables and it just became this huge mess very, very quickly."

Organisers said they brought forward a scheduled break in play so that the stadium security and Victorian police could deal with the crowd.

Police said they were called to the stadium after receiving reports of the chair pyramid being built.

"We helped to calm the situation down and stayed until the end of the event," a police spokesman told AFP, adding that there were no reports of assaults and no one had been arrested or charged at this stage.

Another spectator said the competition winner, world No. 1 Michael van Gerwen, had a look of "pure disgust" at the chaos, Melbourne's The Age reported.

Stadium organisers said in a statement that the "senseless behaviour of the mindless minority was deplorable and their wanton acts of destruction an absolute disgrace".

The stadium's chief executive Paul Sargeant said there would be a review of the incident and how it was handled, but added that the images and videos posted on social media "make the situation look worse that it really was".