Thirty-three skulls and skeletal remains have been unearthed at a hospital in Sri Lanka while conducting excavations for a new building, an official said on Thursday.

Human bones were found on November 27 by a group of construction workers at a hospital in the central hilly town of Matale in Sri Lanka. Since then the number of skulls have increased to ten and then jumped to 24 before hitting 33.

"They were digging to lay the foundation for a bio-gas unit for the hospital," Police spokesman P. Jayakody told media.

Once the human bones were brought to the attention of the hospital authorities, the hospital's Medical Superintendent Arjuna Tilakaratne had contacted the police in the small town.

Subsequently police arrived at the site and secured it for further excavations. Skeletal remains of 33 people have now been uncovered by investigators, according to reports.

Police have declined to comment on how the skeletons came to be at the location but insisted that investigations would continue.