Authorities in Papua New Guinea's Madang province are working with a mining company to establish the cause of suspected poisonous fish.
The Madang Administration has temporarily banned sale and consumption of fish in the province.
This follows reports that a Rai Coast man died after eating fish which local villagers claim was poisoned by a toxic substance.
Operators of the Ramu Nickel Mine in Madang deny that a recent slurry overflow at its Basamuk Bay refinery is linked to the problem.
But a local level government president in Rai Coast district, Amili Deide, said suspicion was raised after local waters turned blood red last month.
"At the moment, all of my community in the Rai Coast area, and al of Madang, they're very frightened to get the fish from the sea. I can tell you that the government is very concerned about that. They're working around the clock to rectify the problem," he said.
The Community Affairs Manager for Ramu Nico, Albert Tobe, warned false reports were being circulated in the mainstream media as well as social media about the cause of fish dying.
The NBC reports him saying these stories have created fear amongst the people and they have stopped going out to sea to fish, as well as sell fish at the markets.
Mr Tobe has assured the general public in Madang that Ramu Nico's Deep Sea Tailing Placement system - used to dump mining wastes into the ocean off Basamuk Bay - is safe.
However, Mr Deide said that after the recent discolouring of the sea, villagers had grown fearful of consuming fish or any sea organism.
"Before that everything was alright. The sea environment and everything was okay, before something polluted the sea. All of that area was covered blood red."