Organizers of the Miss Vietnam World contest cancelled the audience choice award Thursday, following the discovery of weaknesses in its e-election system.
The results for the category were expected to be announced on Saturday at the contest's final ceremony.
However, on Wednesday afternoon, organizers say they found votes for certain competitors increasing continuously and dramatically.
The e-votes were cast via SMS and on the contest's website.
An investigation conducted by the contest organizers later found that some people had hacked into their system using software that automatically generates votes for certain contestants.
The organizers say they didn't bother sorting through the votes because, they feared, it would take too much time.
Moreover, they feared that the results would lack genuine authenticity even after the fix.
"We reached this difficult decision with great reluctance, but we had to make it for the sake of the competition's fairness," Nguyen Trong Hien, representative of organization committee, said at a press briefing Thursday.
Hien apologized to audience voters on behalf of the organizers.
According to Hien, audience members who cast a vote via SMS for VND5,000 (US$0.25) would have their fees returned.