The mines' delivered 268,596oz of gold and 7808 tonnes of copper for its Oceana's first-half trading period to the end of June.
This time last year Oceana had produced 272,352oz and 10,277 tonnes of copper.
In June, Oceana increased its calendar 2018 production guidance range to between 500,000oz to 540,000oz and up to 16,000 tonnes of copper.
Of its four mines, Macraes in East Otago made the largest contribution for the first half, with production at 94,786oz; booking a 13% quarter-on-quarter lift.
Oceana chief executive Mick Mr Wilkes said the second-quarter gold production of 142,950oz was 14% higher compared to previous quarter of 2018, which reflected stronger production across all its mine assets.
Copper production at the Didipio mine in the northern Philippines for the period was 7808 tonnes.
He said at Macraes the 13% quarter-on-quarter increase in production was related to processing higher grades to get better recoveries, delivering 94,786oz of gold.
Mr Wilkes said the first-half production of 268,597oz was "broadly in-line" with the corresponding period a year ago, noting at Haile, South Carolina, there was a "steady state" of operations during the six-month period which offset lower production at Didipio in the Philippines.
He said at Haile the quarter-on-quarter production increase was mainly attributable to improved plant availability and utilisation rates.
Gold recovery had remained steady in the low 80% range and Mr Wilkes said progress was continuing with installation of an upgraded fine grind circuit to further improve recoveries and its commissioning was expected early next year.
At Didipio, Mr Wilkes said the 30% quarter-on-quarter production increase came from the continued ramp-up of underground operations and implementation of a revised mine plan.
At Waihi, which produced 39,320oz of gold for the half year, the 12% quarter-on-quarter production increase came from better equipment utilisation and higher mill throughput.
Oceana has begun resource consenting at Waihi, to open up a new underground operation beneath the historic Martha pit; which is closed down. The new mine could add a decade of mine life to the Waihi operations.
Oceana's complete financial and operational results are scheduled for release later this month.
