The two-day rally, one of Malaysia's largest in years, has been largely incident-free despite police declaring it illegal, blocking the organizers' website and banning their official yellow t-shirt and logo.

Thousands of bleary-eyed protesters who slept on streets near the city's Independence Square woke Sunday to mass exercises and a resumption of the previous day's carnival-like mix of speeches, sing-a-longs, prayer and the ubiquitous snapping of selfies.

Initial crowds appeared smaller than Saturday, when police said 29,000 had gathered, while the rally's organizers – electoral-reform pressure group Bersih said 200,000 had turned out.

The rally got a shot in the arm late Saturday when 90-year-old former premier Mahathir Mohamad made a brief appearance.

Mahathir, who did not address the crowd, has led calls for Najib's ouster, accusing him of corruption and misgovernance.

Still a ruling-party heavyweight, Mahathir's attendance was a surprise as he was known through his 1981-2003 rule for squashing such protests.