Johannesburg police say they will use helicopters to fly over some of the city's malls as part of a crime prevention operation ahead of the festive season.

More than 20 shopping centres have been robbed in Gauteng in recent months.

Eyewitness News reported on Monday that several centres in the city have increased the number of security guards patrolling their premises.

Johannesburg police say they have also been doing their bit by monitoring the situation from the skies.