A popular Christchurch swim spot has been forced to close after beach-goers noticed a foul odour filling the area.

A would-be swimmer told the Herald they noticed an “ungodly, heavy smell”, which they likened to sewage, as soon as they opened their car door on arrival at Corsair Bay.

In response to questions from the Herald, a Christchurch City Council spokeswoman said contractors were looking into the issue.

Just before 2.30pm, the spokeswoman said the beach, including the carpark and tracks, had been closed while contractors investigate the stench.

“You can see the liquid flowing down the pathway on to the beach itself and probably into the sea from there,” the beach-goer said.

Corsair Bay in Christchurch has been closed after a report of a foul smell coming from an apparent leak. Photo / Supplied

Video shows a small stream of water flowing down a path towards the beach from a leak near a toilet block, where a puddle can be seen bubbling.

“Other people were commenting on the smell,” the witness said, adding that it “had me retching”.

The situation comes as people around the country flock to the beach as a heat-streak affects much of New Zealand.

The current temperature in nearby Lyttelton has reached 29.1°, while the central city is experiencing 30.1° heat.