The DA claimed to be well ahead in by-elections in Mitchells Plain and Parow North on Wednesday in what is seen as a crucial test of support before the national election on April 22.
"We've had an excellent turn out so far," said Wayne Smith, a Democratic Alliance member keeping watch at the voting station in Imperial Primary School in the mainly coloured area of Mitchells Plain in the Western Cape.
"At the moment (1pm) more than 300 people have cast their votes for us at this station alone. As far as I know the other parties are still only in the double figures.
"The trend is the same at the other stations. If the DA wins this ward, then the entire Mitchells Plain area will be blue (the colour of the DA banner)."
Voting stations in Ward 2 in Parow North and Ward 79 in Mitchells Plains were quiet throughout Wednesday morning, with most people expected to cast their votes after work.
Ward 2 includes the suburbs of Belville, Boston, Parow, Parow North and Vredelust. Its candidates include Vincent Black for the Congress of the People, Karen Grobler for the African National Congress and Marguerite van der Walt for the DA.
The DA won the ward with 83 percent of the vote in 2006.
Ward 79 includes the suburbs Beacon Valley, Eastridge and Portland. It was held by former Independent Democrats councillor Dennis Williams who recently joined the DA.
Williams, who narrowly defeated DA candidate Jacobus Majiet in an election in 2006, is the registered candidate for the DA on Wednesday.
Charmaine Marman is standing for the ID. The other candidates in the ward include Hayley Oswell for COPE, Salama Michaels for the ANC, David Nero for the Universal Party and Cheryl Philander for the African Bond of Unity.
The head of COPE's policy research unit, Farouk Cassiem, said the by-elections would allow the party to test its support among white and coloured voters.
"In Ward 79 COPE will test its strength relative to the DA, ID and the ANC in a mainly coloured community," he said.
"In Ward 2, which is out and out DA territory, COPE will get an opportunity to gauge how the mainly white community will respond to the party's appeal to South Africans to join with it to create a truly, united and non-racial South Africa."
COPE competed in a by-election shortly after its launch late in 2008 when it took six seats from the ANC in City of Cape Town by-elections.
It entered the election too late, however, for it to register its candidates under the COPE banner.
Gerhard Herselman, a businessman in the Parow area, said at a station at Parow North Primary School that all races had turned up to vote for COPE. Most voters, however, were sticking to the DA.
"My customers came to vote this morning and saw me supporting COPE, they couldn't believe it," he said.
"They expected me to be in the DA."
Herselman said he had grown up supporting the National Party before switching his support to the DA. Now he was a loyal COPE supporter.
He said most people in the Parow area were white, elderly and conservative.
COPE was a new idea to them and they needed time to get used to it, he said.
"The reason I joined Cope was that it had no baggage from the past. I want to be associated with a party that can make a contribution to a better country. I am sure support for the party will grow."
An elderly woman, who asked not to be named, also cast her vote at Imperial Primary School. She said she voted for the DA because it delivered services and was tough on drugs.
Richard Stephenson is competing in Ward 79 for the newly-formed Cape Party which is pushing for the independence of the Western Cape from South Africa.
He said voters were slowly taking to the party's slogan of "Kaap vir die Kapenaar (Cape for the Capetonian)".
"We have had a lot of good feedback from people, but I suppose today is the test," he said.
One voter gave a stern warning to DA members on duty at the Ward 2 station at Tygerberg High School.
"You people have run a rubbish campaign," he said.
"I got just one black and white pamphlet. Don't get apathetic. You rely on the fact that us poor bastards have got nowhere else to put our vote." - Sapa