A sewage spill in Marina da Gama has resulted in the City of Cape Town prohibiting any recreational activity in the Sandvlei Nature Reserve estuary.

The council said spills in the Marina da Gama and Sand River Canal sections of the nature reserve meant the water posed an "elevated risk to human health".

People have been warned to avoid contact with the water after tests showed the presence of high levels of faecal coliforms. 

Fishing has also been prohibited but the land section of the reserve is not affected.

"The city will continue to monitor the water quality. In the meantime, signage has been erected advising visitors to the water body to exercise caution," said Julia Wood, manager at the City of Cape Town biodiversity management branch, environmental management department.

"Members of the public will be informed once the affected area is safe again for recreational use. 

"The city apologises for any inconvenience caused as a result of the closure of the water area and thanks the public in advance for their co-operation."

Sandvlei is home to the Imperial Yacht Club and is a sea scout base. It is also popular with kayakers and windsurfers.