Doctors are examining bones retrieved from a canal near Government House yesterday but have yet to determine if they are of human origin.
The results of the examination of more than 25 bones will take time, but initial checks found some of them look similar to a human pelvis and shin bone, according to doctors from Police General Hospital's Institute of Forensic Medicine.
Thorough testing of the DNA in the bones, found in several fertiliser bags, is needed as some appear to be larger than normal human bones, the doctors said.
The bones were found yesterday morning in Khlong Phadung Krung Kasem, which runs along one side of Government House, by city workers cleaning up the canal.
The clean-up was part of work to turn the canal into a floating market, a plan initiated by the prime minister.
Members of the police bomb squad, soldiers and workers from the Dusit district office and Bangkok Metropolitan Administration's drainage and sewerage department, along with the Ruam Katanyu Foundation, retrieved the bones.
The bones are thought to make up the legs, hips and backbones of people who died at least two years ago. They were handed over to Nang Loeng police to pass them to the Forensic Medicine Institute of the Royal Thai Police Office for examination.
Experts from the Office of Police Forensic Science have also joined the process to identify the bones.
During the canal cleaning, other items found included a white object, believed to be an electrical circuit panel, and a tear gas canister no longer in working condition.
Khlong Phadung Krung Kasem is near parliament and Government House.
Some believe the bones might date back to protests in 2008, when the People's Alliance for Democracy laid siege to the seat of power in an eight-month anti-government protest.