"Working smart means that we are going to succeed in ensuring convictions," said Mthethwa, addressing police members and parliamentary members at the launch of the R500 million Plattekloof Laboratory in the city.
Mthethwa praised the police's forensic division for making progress in reducing its backlog in cases in the last three years.
The number of cases lodged at forensic laboratories that were older than 28 days old, have been reduced by 30% in last financial year over 2010/11, following a 60% decline in backlogs between 2009/10 to 2010/11.
Mthethwa said the detective and forensic training courses that the police are currently running would also help strengthen the forensics division.
He said the government had no intention of privatising forensic laboratories, adding that two years ago when he had met with his UK counterpart, he was told that Britain's move to privatise forensic services had been mistake, as it had only resulted in raising costs.
The new centre, which serves the Western Cape and several districts in the Northern Cape and Eastern Cape, replaces the old forensics centre which was being leased in Delft, and is one of four forensic laboratories in the country (with the others in Port Elizabeth, Pretoria and Durban).
Police Commissioner Riah Phiyega said the centre would play an important role in combating violence against women and children involving substance abuse.
She pointed out that figures from the 2011/12 financial year revealed that of total cases received in the biology section alone - more than 50% were related to rape and murder cases.
The new centre, which has been operating since November last year, will focus on among other things, DNA analysis, identifying drugs, causes of fires, polygraphs, analysis of gun shot residue, handwriting analysis, blood-stain analysis and 3D facial recognition.
The police, she said, would continue to increase its capacity in the critical area of forensic services and added that this had been identified by her as a key area in fighting crime.
This would be complemented by the setting up of a DNA database, she said, following the envisaged passing of the DNA Bill, which is currently in Parliament.
A number of other countries have similar legislation in place, including Brazil, which in May enacted DNA database legislation into law.
She also planned to bring the various roleplayers together to find ways to expedite the reporting processes to improve the criminal justice system.
The state-of-the-art centre includes a system of rails running the length and breadth of the building (running about 800m in length) and 50 boxes in which collected evidence is then channelled from nine kiosks, where they are received from investigating officers, to the correct department for investigation.
The system, which is used in European forensic centres, will go some way in resolving the problem of evidence being misplaced or tampered with, as the boxes can also be tracked using a biometric system - which is also used to open the boxes.
Head of forensics services, Lieutenant-General Julius Phahlane, said the division achieved a criminal conviction rate of 94% in the last financial year (2011/12) - up from 63% in 2009/10 financial year.
However, just 77% of evidence was processed within 28 days, against a target of 92%.
Phahlane said the low performance was due to a lack of capacity in the forensic division, but added that 800 more staff would be employed in the four laboratories this year, in addition to the 6 930 staff that were already employed in the division.
Despite this and the increasing amount of evidence submitted, the backlog in processing evidence has come down - from 59 023 on 1 April 2009 to 11 310 on 1 April this year.
However, Phahlane said the forensic division was struggling with a massive work load around analysing drugs - and the backlog had more than doubled from April 1 last year to April 1 this year.
The forensics division uses hi-tech equipment, such as a R1.5 million camera which can take panoramic shots necessary to accurately record the scene of a crime. Phahlane said such equipment was necessary if the police were to outsmart criminals.