The company, majority owned by Canada's Barrick Gold Corp, is grappling with a long-running tax dispute in Tanzania where it operates all its mines. It has cut output by a third since the government banned the export of mineral concentrates in 2017.
Acacia said gold production for the first quarter at North Mara was 66,324 ounces - 14 percent lower than last year. This was mainly due to unexpected movement of rock in its Gokona underground mine and an excavator breakdown in the Nyabirama open pit.
Overall, gold production fell 13 percent to 104,899 ounces in the first quarter. Jefferies analysts said this figure was below their consensus.
The company's shares were down about 3 percent in early trade.
Acacia in March had introduced a revised mining plan for both the underground and open pit mines to address production problems at North Mara and is currently targeting total production of 500,000 ounces to 550,000 ounces in 2019.
In March, the company had also said it stopped an overspill at the North Mara mine and it was working to prevent any further problems.
(Reporting by Pushkala Aripaka in Bengaluru; Editing by Bernard Orr)