Deadly fires have broken out around South Africa's coastal city of Cape Town, destroying hundreds of homes and killing three people during a sweltering heat wave, a city spokesperson said on Tuesday.

Dry conditions in Cape Town's summer, characterised by often gale force winds, have sparked brushfires in the mountains as well as accidental home fires in the shacks that fill informal settlements around the city.

"Over the weekend, in informal settlements we responded to about 27 incidents.

There were three deaths that I know of," said the city's chief fire officer Ian Schnetler.

Nine fires raged on Monday, casting a heavy pall of smoke over the city. Schnetler said most firefighters were battling a blaze in Gordon's Bay, a popular holiday retreat, where authorities ordered people to evacuate.

"We have got the majority of our fire and rescue resources at this incident and they have been assisted by various other firefighting agencies. Prevailing weather conditions are making firefighting very difficult and preventing aerial firefighting," Schnetler told AFP.

A statement from the city said two helicopters and 54 firefighting vehicles were at the scene of the blaze, which had already burned nine properties, gutting two of them.

"The South African Weather Office indicated that the current weather conditions are unlikely to change within the next 24 hours, which will hamper the efforts of firefighters," read the statement.

Firefighters are on Tuesday still battling a raging runaway fire in Gordon's Bay in Cape Town, the Disaster Risk Management Centre said.

"City firefighters have been busy with firefighting operations since 3am on Monday and throughout the night. They are still busy bringing the fire under control," said spokesperson Wilfred Solomons-Johannes.

The fire started in the Overberg District area and spread to the Streenbras Dam Catchment area.

Solomons-Johannes said two houses were damaged and one gutted by the blaze. Available standby and off-duty fire-fighters were called to help — bringing the number to 150.

"This situation once again illustrates the need for citizens to exercise extreme caution to reduce fire risk when such dry and windy conditions are being experienced," said Solomons-Johannes.

Residents living along the Gordon's Bay's mountain slopes (Upper Watt, Suikerbossie, Valley and Kloof Streets) were evacuated around 7pm on Monday.

Residents were urged to exercise caution in the vicinity of fires.

"We are keeping a watchful eye on all the fires...The South African National Defence and Air force has been requested to be on standby to assist with aerial firefighting."

Life-threatening emergencies could be reported to the city's public emergency communications centre on 107 on a landline or 021-480-7700 from a cellphone.

AFP