Dhammananda Bhikkhuni has lodged a petition with the Department of Women's Affairs and Family Development (DWF) claiming she and a group of female monks were blocked from paying respects to the late King last month.
The petition was signed by more than 10 bhikkhuni, or female monks.
The group claimed they were among 72 bhikkhuni blocked by Asst Prof Teerapak Chaichana, a teacher at a monks' university who was in charge of screening monastics at the Grand Palace on Dec 9.
The petition, presented by Kanjana Suthikul who represented the bhikkhuni, has two requests. It calls for an end to discrimination against Theravada bhikkhuni who want to pay respects to the late King at the Grand Palace, and to treat them as Buddhist monks without sexual discrimination.
The group also asked Mr Teerapak to apologise to the bhikkhuni before the committee considers issues of preferential treatment on the basis of gender under the DWF. It also wants the media to be allowed to record the apology.
Ms Kanjana said the group had to lodge the petition to forge an understanding that bhikkhuni are not illegal.
"We want to set a legal precedent that officials cannot violate the constitution which protects gender equality and religious rights," Ms Kanjana said.
Mr Teerapak is said to have told the Dhammananda Bhikkhuni and the group they were "illegal" and treated them with contempt.
In the report, Dhammananda Bhikkhuni also explained Theravada bhikkhuni were ordained in Sri Lanka, so they were not part of the Thai clergy.
The rules prohibiting female ordination by the Thai clergy do not apply to them. The group also claimed they had received the palace's permission to pay respects that day.
Ms Kanjana said it remained unclear which law Mr Teerapak cited when he said bhikkhuni were illegal.
She said bhikkhuni are not illegal but the matter is not covered under the Clergy Act.
Bhikkhuni should not be illegal in this case, she added.
Mr Teerapak told the Bangkok Post that he didn't allow Dhammananda Bhikkhuni's group to enter because they lacked certification.
He said that to get in, the group needed certification that they are monastics from the clergy, but they didn't have it.
The centre assists Buddhist monks and novices, which have nothing to do with bhikkhuni, Mr Teerapak said.
He declined to comment on the petition.
DWF officer Panida Hansawasdi, who received the petition, said the office will verify the document and pass it on to a panel to consider whether the case breaches the Gender Equality Act.
Angkhana Neelapaijit, a National Human Rights Commission member, also raised concerns over the issue, saying freedom of religion is included in the constitution as well as international conventions.
Ms Angkhana said the bhikkhuni have long faced problems gaining acceptance from the Sangha Supreme Council of Thailand, making it hard for them to live with freedom of religion.
The group will file another complaint to Dusit district court on Jan 19 regarding the case.