“We received reports yesterday [Monday] that political parties will be embarking on protest action; some are very peaceful and have displayed placards over the bridges but some are obviously violent with burning of tyres and placing of rocks on the roads. This is creating a bit of chaos in our city and roads,” Mr Sun said in a statement.
In Cape Town, a port city on the southwest Coast where Parliament is located, the city authorities approved protests for Tuesday afternoon.
Thousands are expected to march in separate protests in support or against President Zuma.
Mr Zuma faces his eighth motion of no-confidence on Tuesday afternoon and, for the first time, it will be a secret ballot.
But the ANC — which holds a large majority in parliament — said it expected its members to easily defeat the no-confidence motion.
Several opposition parties led thousands of anti-Zuma protesters to the national assembly in Cape Town ahead of the parliamentary session due to begin at 2:00 pm (1200 GMT). “ANC MPs now have no excuse.
They must use their vote... to remove Jacob Zuma,” the main opposition Democratic Alliance party said after the speaker of parliament made a surprise decision Monday to hold the ballot in secret. Zuma has survived several previous parliamentary votes that were held without secret balloting.
A 201-vote majority would be needed to remove him from power, and the ANC holds 249 seats in the 400-seat parliament. His cabinet would also be forced to resign.
“Mbete’s decision was made knowing that Zuma will be secure,” said Darias Jonker of the New York-based Eurasia political analysis consultancy.
“The vast majority of ANC MPs are not willing to risk the stability of the party in order to remove Zuma in this fashion.”
Zuma, 75, is due to step down as head of the ANC in December, and as president before the 2019 general election — lessening pressure for his party to trigger imminent change.