Updated at 2.15pm: More than 500 youngsters queued from before dawn on Friday outside the Hong Kong Convention and Exhibition Centre for the opening of the Comics Festival and Game Fair.
The annual event began on Friday at 11am and would end on August 1.
As many as 98 exhibitors - including 12 from the mainland - would show their newest TV games, toys and figures based on their comic series.
Ming Pao Daily reported that many visitors - mostly teenagers - had a few thousand dollars cash with them to buy the gadgets.
Local radio quoted the man first in the queue as saying a minor uproar started when an internet game exhibitor played games with people in the queue and then gave some cash to the winners.
''I suddenly heard sounds of quarrelling from behind. And then a lot of people went to see what was happening and started roaring,'' said the man, surnamed Mok.
