"The commissioners have yet to tell me why I have not been endorsed as a senator," Rosana said at the EC headquarters.

She said they convened a panel to investigate her case but had never called her to defend herself against the allegations of breaking electoral laws.

Rosana is one of 18 Bangkok senators waiting to be endorsed.

An EC subcommittee recently accepted a complaint filed by candidate Paruey Chansakul that Rosana had posted her biography on the website of her employer - the Thai Holistic Health Foundation - from April 11 to 14.

She is also among other well-known senatorial candidates such as Nitipoom Nawarat and Boonyord Sooktinthai, who participated in People's Alliance for Democracy (PAD) rallies, and who are still waiting to be endorsed.

"I will sue the commissioners if they nullify my victory," said Rosana, responding to a report about comments made by EC member Prinya Nakchudtree in an interview where he said senatorial candidates who took to the PAD stage would be disqualified.

Rosana said that while she did appear on the stage at a PAD rally, she had not tried to canvas support for, or even mention, her own senatorial campaign.

In the meantime, a criminal court accepted Rosana's complaint against Paruey, who she said had accused her of violating election laws. "As the court has accepted my case, it shows that the allegation against me should be dropped as it has no truth," said Rosana.

The EC has so far endorsed 163 of 200 winners in the April senatorial elections.

EC chairman Vasana Puemlarp said the commission was considering complaints against the 37 candidates who have not been endorsed. He declined to say whether any of them would be disqualified.