First-half revenue increased 21% to $US402.2 million ($NZ593.3 million) and after-tax profit grew 45% to $US89.1 million, compared with a year ago, and cash reserves increased quarter to quarter by 45% to $US148.9 million, including $20 million in undrawn bank facilities.
Net debt for the second quarter was reduced from $US248.1 million a year ago to $US103.9 million.
Oceana chief executive Mick Wilkes described the first half-result as a "robust" performance.
"Each of our operations delivered impressive results that we expect to continue for the remainder of the year," he said in a statement.
In the first half, Oceana’s Macraes mine in East Otago topped gold production, delivering 94,800oz, Haile in South Carolina returned 75,700oz, output at Didipio in the northern Philippines was 58,800oz, plus 7808 tonnes of copper, and Waihi in the Coromandel delivered 39,300oz.
Gold production was slightly down on a year ago by about 3800oz.
Oceana recently increased its calendar 2018 guidance range to between 500,000 and 540,000oz of gold, and between 15,000 and 16,000 tonnes of copper, sustaining costs in a range of $US725 to $US775 per ounce sold.For its half year, Oceana produced 266,421oz of gold.
The cost of producing an ounce of gold fell from $US744 in the first half to $US696 in the second half.
"Over the past 12 months we have increased our cash balance by nearly 60% and cut our net debt by almost half, which reflects the strength of our assets," Mr Wilkes said.
Oceana declared a another semi-annual 2c dividend.
Mr Wilkes said all operations were delivering strong performances, its exploration programme was achieving significant results and and organic growth opportunities, including the Martha Project at Waihi and Haile expansion, were all "progressing well".
"Oceana Gold is well positioned to continue delivering positive results," he said.
Of Oceana’s total $US220 million credit facilities $200 million remained drawn and at the end of the first half of 2018, the net debt position was $US103.9 million, nearly 50% less than at the same time last year.
