Beaches near Umhlanga have been closed, following a chemical spill in Durban.

The spill appears to have originated from a chemical warehouse fire in Umhlanga that was caused during unrest that gripped KwaZulu-Natal this week. Other sources are being investigated.

On the advice of the provincial economic development, tourism and environmental affairs department and Ezemvelo KZN Wildlife, the eThekwini municipality decided to close beaches north of the uMgeni estuary.

In a statement, the municipality said the decision was made due to the potential "environmental and human health impacts" that came with chemical spillage into the Umhlanga Lagoon.

On Thursday, the municipality announced that fish and crustaceans killed in the Umhlanga and uMdloti Lagoons and some beaches were the result of a suspected chemical spill.

The public has been advised "to refrain from all recreational activities, including fishing or surfing, bait collection and picking up of dead species" in the area.

The closure will affect Beachwood, Virginia, Glenashley, La Lucia, Umhlanga Main and Bronze, uMdloti, La Mercy and Tongaat beaches, including tidal pools.

"Authorities are engaging with other local municipalities further north as a precautionary measure. The public are advised to avoid the beach area at this time until it is deemed safe," the municipality said in a statement.

"Extensive environmental impacts are being reported at Umhlanga and uMdloti Lagoons and beaches in the vicinity and these have contributed to killing numerous species of marine and bird life. The pollution is considered serious and [it] can affect one's health if species are collected and consumed. Lagoon and seawater contact must also be avoided."

Some residents in areas north of Durban are also reporting smoke residue from burnt chemical products.

"The public can only smell it from time to time, depending on the wind direction as it dissipates. Residents are advised to close windows and doors and put wet cloths over vents until smoke clears as a precautionary measure," the statement read.