Papua New Guinea's major mine operators have been warned by the prime minister to comply with safety and operating standards.
James Marape issued the warning after the government confirmed the temporary closure of the multi-billion kina Ramu Nickel mine in Madang province.
Mr Marape told NBC the shutdown would only be temporary pending further investigations over the recent spill of mine slurry off Madang's coast.
The Conservation and Environmental Protection Authority has confirmed that 200,000 litres of toxic slurry spilt into the sea from the mine's refinery in August.
The spill turned the sea red in Basamuk Bay and was linked by locals to numerous health problems.
The Madang provincial administration has put a temporary ban on catching and consumption of fish.
Mr Marape said the company's executives were expected to meet with his government to find an amicable solution.