Several neighbours in the West Harbour suburb say the smell from the nearby lagoon is becoming unbearable and they are unhappy the Otago Regional Council has been telling them they will have to put up with it.
"It's revolting," Gerard Palmer, of Eagle St, said. "No-one's happy about it."
In response, regional council services manager Jeff Donaldson said the smell was the result of a natural occurrence and nothing more could be done.
David Humphrey, who has lived in Burkes for 25 years, said the lagoon had become increasingly odorous in the past couple of years.
"It smells like rotten eggs," Mr Humphrey said. "It's offensive and hard to live with."
Edith Leigh, who lives next door to Mr Humphrey, said the lagoon had emitted a smell during spring in past years.
But this year the odour had started at the beginning of winter and had become much stronger, she said.
"I keep thinking my daughter's nappy needs changing," Mrs Leigh said. "When we have visitors over it's really embarrassing."
Several theories about the cause of the stench have been put forward.
Carol Peddie, of Finch St, wonders if it is sewage.
She believed officials were looking for illegal sewerage outlets in the area earlier this year or late last year.
Sue Parkin, of Eagle St, also thinks the odour is distinctly "pooey".
Others think sea lettuce - an edible green algae - is the most likely culprit.
The rotting leaves of sea lettuce produce large quantities of toxic hydrogen sulphide gas.
Mr Palmer said the sea lettuce had been growing only in one corner of the lagoon but had "gone rampant" in the past month, and now covered a large portion of the lagoon.
He wonders whether reduced dredging of Otago Harbour, combined with nutrient run-off from residential development along the hill above the lagoon, is producing ideal conditions for sea lettuce to flourish.
"The silt is building up in the lagoon. Only two years ago we would see sharks and seals in there. Now they couldn't paddle in there," Mr Palmer said.
"In the past, occasionally there was sea lettuce, but the lagoon could flush itself. But not any more."
Mrs Leigh said she and other residents had phoned the Otago Regional Council but had been told the smell was a natural occurrence and that they would have to put up with it.
The regional council needed to properly investigate the cause and what could be done about it, Christine Johnston, who lives just above the lagoon, said.
"They should get scientists in to look at it," Ms Johnston said.
Mr Palmer believes, at a minimum, the lagoon needs to be cleaned out.
"They have to get it flushing again," he said.
Mr Donaldson, of the ORC, agreed the smell was being caused by a shallower lagoon promoting the growth of sea lettuce.
"Shallower exposure to sunlight and increased heat are encouraging the plant to grow more widely," he said.
The silt build-up "could be a natural process" from the harbour or "possible run-off".
But while the council had investigated complaints and would continue to monitor run-off, there were no other plans to try to remedy the situation.
"If it is a naturally occurring process, we have no control over it," Mr Donaldson said.
"Without proof of a specific incident, or a breach of the RMA [Resource Management Act], we have no ability to do anything further."
