Airlocks and ''positive pressure'' will be used to prevent contamination of evidence in a new $105 million Australian Federal Police Forensic research complex.
Fears of potential contamination in the ageing forensics centre at Weston have led police to send some evidence to New Zealand and the United States for examination.
But the new centre to be built on the AFP site at Majura will be capable of examining evidence on behalf of all Australian police forces, Parliament's Public Works Committee has been told.
Assistant Police Commissioner Julian Slater said many evidence examination rooms at the Weston centre did not have anterooms or airlocks to protect evidence from contaminants.
''In many rooms we are actually entering the room directly from an open corridor,'' Mr Slater told the committee recently.
''The rooms that get most used and that are the most important to us have airlocks.
''You have the opportunity to move into an airlock space, don protective clothing to avoid bringing contamination to your examinations and then step into the examination room to conduct those examinations.''
Mr Slater said the airconditioning system used at the Weston centre was not designed to help protect evidence.
''We do not have what is best practice, which is positive pressure environment.
''Positive pressure environment means that, by virtue of those arrangements, air is always flowing out of the room, so contaminants from outside of the room do not move on air into the examination spaces. That is a particularly important consideration for us.''
Mr Slater said detailed plans were being developed to enable staff, equipment and evidence to be moved from Weston without compromising investigations.
''Certainly if we are midway through a murder investigation and we have exhibits partially complete, we would not be moving to that new site and finishing it in the new site. We would finish our examinations [at Weston],'' he said.
A dedicated training laboratory would be built at Majura to reduce the risk of evidence being contaminated during training exercises.
The new centre would be able to meet the AFP's forensic science needs for at least 20 years and could also provide service for other police forces.
The Majura centre is due to open by mid-2015.
It will be large enough to simultaneously manage the investigation from several crime scenes or from a major incident, such as a Bali-style terrorist attack in Australia or a neighbouring country.
The centre would be built on the same site at a current police driver training track. A replacement track would have to be constructed.