In an unusual move to clean up the force, the city's 900 male traffic police are being stripped of their ticket books.

Instead, an elite corps of 60 women traffic police - with 22 vehicles - will have sole responsibility for handing out fines.

"There is a perception that the people holding the ticket books commit acts of corruption," police chief Alejandro Gertz told a news conference. ''That's why we are coming up with an adequate and sensible response."

The 'little bite'

Mexico City police are infamous for shaking down motorists over traffic violations - real or imagined.

Alejandro Gertz: 'An adequate and sensible response'

When traffic offenders are pulled over, they know the routine - face a fine that can run to more than $60, or pay a small bribe called the "little bite".

But from Monday, if a traffic officer stops someone, he must call one of the two-women teams.

The mini force will handle all of Mexico City, which has a population of some nine million, but Mr Gertz said more units would be added later.

"Police-women have a high esteem for the people," he added. "That's why there is much less tension - and the work they will carry out will be very notable."

According to Reforma newspaper, Mexico City police handed out 1.6 million tickets last year.