Residents of a town on Tasmania's west coast say pollutions has turned the Queen River a deep shade of orange.

The river was used for almost a century until the 1980s as a drain for the nearby Mt Lyell copper mines, during which time an estimated 100 million tonnes of sulfidic tailings were dumped into the river.

This has left the Queen River fairly transparent but rusty in colour.

Now, locals from nearby Queenstown say the colour has intensified dramatically.

They speculate that the Mt Lyell copper mine has leaked a significant amount of acid in recent months.

The mine - now owned by Copper Mines of Tasmania (CMT) - has been in care and maintenance mode since 2014, but the owners have recently announced plans to reboot operations.

An increasing copper price has led the Tasmanian Government to commit $9.5 million to attempts at restarting the mine, which include reparation works such as tunnel and pipe repairs and water drainage.

CMT spokesperson Deshnee Naidoo says the revived mine will not have the same environmental issues as its previous iteration.

“The team has now come up with innovative ways as to how it can restart,” she told reporters in April this year.

“We are not thinking about restarting CMT in the way CMT has been running for the last 100 years.

“We are thinking about restarting CMT with very green technology across the board to do things differently to make sure that CMT ... can start and stay open for a sustainable amount of time.”

But with the latest allegations of a leak, Tasmania’s EPA has launched an investigation that will include the collection and testing of water samples to be discussed with Copper Mines of Tasmania.

An initial lab analysis of the water samples is expected to be complete within a week.