The Solomon Islands Ministry of Health has warned people living in villages below the tailings dam of the Gold Ridge Mine on Central Guadalcanal not to use water from streams for drinking, cooking and bathing.
The warning followed days of heavy rain last week which caused the tailings dam to overflow onto the streams below.
The Ministry said arsenic could have ended up in the streams and therefore it advised villagers also not eat fish and eels from them as well as animals using them.
The warning was given despite an earlier denial by the Chair of the Gold Ridge Community Investments, Walton Naezon, of the tailings dam overflowing arsenic into the stream.
The Premier of the Guadalcanal Province, Anthony Veke, told local radio the incident was worrying his government.
Mr Veke said disaster authorities were considering despatching water tanks to the villagers immediately.