Canada's Barrick Gold Corp, the world's largest gold miner, estimated a decline in third-quarter gold production amid pressure from the Tanzanian government on its Acacia Mining unit.

The operation has been accused by the country's government of evading taxes for years by under-declaring exports, stalling work at the mines as well exports of its gold and copper concentrates.

Acacia, 63.9 per cent owned by Barrick, said earlier on Thursday that its gold production fell 8.3 per cent to 191,203 ounces in the three months to September.

Barrick Gold estimated it produced 1.24 million ounces of gold in the quarter, less than the 1.38 million ounces produced a year earlier and slightly lower than Deutsche Bank Securities' estimate of 1.29 million ounces.

However, the company, which is scheduled to report its third-quarter results on Oct. 25, said it was on track to meet full-year gold production forecast of 5.3 million ounces to 5.6 million ounces.

"We expect year to end strongly, based on a pick up at key operations," said Deutsche Bank Securities analyst Chris Terry.

Average price for gold fell to $1,278 per ounce during the quarter from $1,333 a year earlier, the company said.

Barrick's shares were marginally down at both New York and Toronto stock exchanges. Acacia's shares recover to trade down marginally after dropping as much as 4.5 per cent.

Shares of Barrick, which intends to cut its debt to $5 billion by 2018-end, are down nearly 3 per cent this year, while gold is up more than 12 per cent.