New roof-top red and blue lights for police cars should yield annual fuel savings worth $800,000.
The lights use LED technology rather than bulbs and can cut fuel consumption by 8%.
The new bars cost about the same as rotating lights, but use 95% less power.
National procurement manager Stan Pope says the new lights will save fuel because they have a lower profile and reduce wind drag.
He also says they will last much longer.
There are about 1700 marked vehicles in the current police fleet.