Centre for Human Rights Research and Advocacy (Centhra) chief executive Azril Mohd Amin claimed that the "militant LGBT" activists had used Bersih 5 to further their own agenda.
In a commentary published by Mingguan Malaysia today, Azril said there were photographic evidence which showed activists promoting LGBT rights during the rally.
"They carried a banner to demanding for their rights to practice their lifestyle and they were not admonished by Bersih 5 participants, nor Bersih 5 leaders or those behind Bersih.
"Doesn't this show a hidden agenda among those behind Bersih 5 in wanting to fight for the rights of the LGBT under the pretext of 'free elections'?" wrote Azril.
Azril, who is also a lawyer, said the organisers of Bersih 5 have never apologised for the appearance of "militant LGBT" during the rally.
However, he did not provide examples of how those carrying banners urging rights for the LGBT community are "militant".
Probe Bersih over LGBT links
Azril also claimed that there has been articles in the west which claimed that the "militant LGBT" movement is gaining steam across the world.
He said the this movement had successfully campaigned for the United Nations Human Rights Commission to appoint an independent expert on Sexual Orientation and Gender Identity (SOGI).
Azril also cited a Aug 11 Washington Times article, which claimed George Soros was a financier of the "transgender movement", to support his claim that the LGBT movement was part of a global conspiracy.
In view of this, he urged the federal government to observe Bersih over its links with the LGBT movement.
"We do not want the right to peaceful assembly by the public to be manipulated by these militants which could result in the spread of a lifestyle forbidden by God," wrote Azril.
This comes after Bersih chairperson Maria Chin Abdullah's arrest under the Security Offences (Special Measures) Act, which police say is over document found in a raid on Bersih's office on Nov 18.
Inspector-general of police Khalid Abu Bakar said she is held over ties to Soros-linked Open Society Foundations (OSF).
Bersih, however, refuted claims that the arrest and detention is over documents seized as there was no mention of this in the list of items seized provided by the police to the electoral reform NGO coalition.
Umno information chief Annuar Musa also claims Maria has links to the United States' Central Intelligence Agency (CIA), a charge Bersih and Maria's family vehemently deny.
Maria was arrested on the eve of the Bersih 5 rally, which attracted at least 40,000 people in downtown Kuala Lumpur.
The rally's demands were clean election, clean governent, empowerment of Sabah, strengthening of Parliament and the right to dissent.
Sosma allows for 28 days detention without trial, but the court will hear Maria's habeas corpus application on Tuesday.