British law firm Leigh Day, representing the families, said it has filed a legal claim at the High Court in London alleging that the London Bullion Market Authority [LBMA] "has been wrongly certifying that gold sourced from a Tanzanian mine is free from serious human rights abuses".
The two men were both aged 23 and died after working at the North Mara Gold Mine, according to the statement.
The facility in northwestern Tanzania is majority-owned by gold miner Barrick Gold Corporation.
"The claimants state that despite a widely reported pattern of systematic human rights abuses associated with the mine over many years, the LBMA has continued to certify gold from the mine under its LBMA Responsible Gold standard," the law firm said.
"The legal issues raised by this case turn on whether a certification body, like the LBMA, can be held legally responsible for a flawed certification process which causes or contributes to ongoing human rights abuses," Leigh Day added.
In response, the LBMA expressed sympathy over the deaths but argued that the legal action had no merit.
"LBMA would like to express its deepest sympathy to the families of all those injured or killed in the course of gold mining in Tanzania," it said.
The first miner died in July 2019 when he was shot by security staff at the facility, Leigh Day said citing the claimants.
The second miner died in December of the same year when he was shot by Tanzanian police.
However the organisation added that its certification operated via "transparent and well-published principles that all refiners must follow".
"LBMA and its legal advisors believe this claim has no merit," it added.
The LBMA has until early next year to respond to the claim, it added.