The Western Cape is to pass a law banning politicians from using blue-light convoys in the province, Premier Helen Zille announced on Friday.

In her State of the Province Address, she said that this would apply to politicians from "any sphere of government".

The only exception would be a genuine emergency.

"And being late for a meeting does not constitute an emergency," she said.

Zille's announcement follows outrage at the arrest this week of a University of Cape Town student who made an obscene gesture at President Jacob Zuma's convoy as it passed him.

Scores of students on Thursday demonstrated in solidarity with the arrested Chumani Maxwele, all flashing the same raised middle finger.

Zille said that law enforcement agencies were supposed to protect innocent citizens against power abuse.

Unfortunately, in South Africa there were cases where the police themselves were accessories to this abuse.

When her provincial executive assumed office nine months ago, one of the first things it did was to instruct the police's VIP protection services to stop using blue lights and sirens on ministerial vehicles unless in exceptional circumstances.

"We did this because we don't believe that politicians should have special rights and privileges that other citizens don't have," she said.

"We share the public's disgust at being forced off the road by blue light bullies escorting self-important politicians."

Maxwele's arrest and interrogation by the president's protection officers was an example of such abuse.

South Africa was a constitutional democracy, not a police State, she said.

"We will therefore introduce legislation... to prevent any politician from any sphere of government using blue-light convoys and sirens in the Western Cape, unless a genuine emergency arises."

This would be done in terms of the provincial government's constitutional competencies for road traffic regulation.

Zille also announced planned legislation to prohibit employees of the province conducting business with it, except in strictly defined and transparent circumstances.

Tender rigging and conflicts of interest were one of the primary sources of corruption in all provinces, she said.