Come June 7, the health ministry will begin conducting post-mortem on human skeletal remains found at grave sites in Wang Kelian, Perlis.

Minister, Datuk Seri Dr S. Subramaniam said the post-mortem was aimed at determining whether the skeletal remains and those found at human trafficking camps at the Malaysia-Thai border were those of murder victims.

He said for this purpose, the ministry had formed the CSI-DVI (Criminal Scene Investigation-Disaster Victim Identification) and the PM-DVI (Post Mortem-DVI) teams.

"The CSI-DVI has been stationed at the recovery site to help in the process of collecting samples, while the PM-DVI team is at the Sultanah Bahiyah Hospital, Alor Setar to perform the post-mortem on the remains," he said in a media conference here today.

On Monday, Inspector-General of Police Tan Sri Khalid Abu Bakar announced the discovery of 139 graves and 28 transit camps abandoned by a human trafficking syndicate in Wang Kelian, close to the Malaysia-Thai border.

Dr Subramaniam said three post-mortem procedures would be conducted simultaneously to speed up the process of identifying the bodies before samples were sent to the Malaysian Chemistry Department for DNA tests.

He added the post-mortem procedures involved several small teams comprising forensic medical, forensic science, forensic dentistry, radiology and DNA teams.

On the DNA database, Dr Subramaniam said it would be conducted on all bodies found and the data would be kept by the ministry and the police.

"We cannot take the easy way out in the process of identifying the victims. As such, we will be isolating the DNA of each body for reference purposes to facilitate further action towards determining the DNA of the person found in each grave," he said.

The minister said as of last night, 15 body bags had been sent to the Sultanah Bahiyah Hospital morgue.

He said the police had also provided a cold storage container which would enable the hospital to hold more bodies for the post-mortem.

On the current dengue fever situation, Dr Subramaniam urged the public to take the necessary precaution and keep their surroundings clean, especially 'hotspots' and dengue areas, following a 16 per cent increase in the number of dengue cases each week, over the past two weeks.

"This (the increase) is caused by the mutation of the dengue serotype virus at the end of April," he said.

He said a total of 1,944 cases were reported between May 17 and 23 (week 20), as compared to only 1,675 cases, the week before.

From January to May 23, the number of cumulative dengue cases stood at 45,070, an increase of 35 per cent (11,614 cases), compared to 33,456 cases for the same period last year.

The number of hotspots also increased from 65 to 70 localities in Selangor, Perak, Penang and Melaka.