OceanaGold, which runs the gold mines at Waihi, plans to invest $US10 million ($NZ15.17m) this year in the search for more gold.
The main focus would be near the existing Correnso underground mine, which is close to Waihi's famous big hole.
The work would add to over 13km of tunnelling, which was done in the second half of last year.
OceanaGold revealed this in statements to sharemarkets, including New Zealand's, where it was listed. It was not saying what it had found, except to declare the results "significant".
The company bought the mine from US firm Newmont last year.
It declared at the time that Waihi had 310,000 oz of gold reserves - the equivalent of 775 gold bars.
In its most recent quarterly report, OceanaGold's profits fell to about a third of what they had been a year earlier.
The price of gold has slipped steadily for four years but has recently rallied.