Democratic Alliance federal council chair Ashor Sarupen has insisted that party leader Geordin Hill-Lewis will continue to serve as Cape Town mayor rather than move to Parliament, saying this approach has proven successful in the past.

"We have seen the best growth in the DA's history when our leader was not in Parliament. Helen Zille was the leader of the party between 2006 and 2009 and we went from being a big player to becoming a party of government," Sarupen told the Mail & Guardian on the sidelines of a media briefing on Wednesday.

The blue party held a walkabout at Mary Fitzgerald Square in Newtown, Johannesburg ahead of its manifesto launch rally, which is set to take place on Saturday.

The manifesto launch is expected to outline the party's plans should it take over government in the 4 November local government elections.

In 2006, Zille was elected mayor of Cape Town and was later elected the party's federal leader in 2007.

In 2009, the DA won the Western Cape with an outright majority of 51.5%, taking the province from the ANC and becoming the first party to wrestle control of a province from the ANCt.

Sarupen said what the party had learnt from the past was that its leader could govern effectively and deliver results. That was what mattered most in his view.

"If the leader can demonstrate through Cape Town that the DA is the best party to trust, that is what matters most."