OceanaGold uncovers high-grade gold zone in New Zealand drilling breakthrough

OceanaGold Corporation (TSX: OGC,OTC:OCANF) (OTCQX: OCANF) ("OceanaGold" or the "Company") announces results from 6 drill holes from the ongoing exploration and resource conversion program at Wharekirauponga, located approximately 10 kilometres ("km") to the north of the Company's Waihi operation in New Zealand.

Wharekirauponga Drilling Highlights (estimated true width): - 14.9 m @ 16.3 g/t Au from 466.5 m, EG Vein (WKP144B) - 5.4 m @ 25.8 g/t Au from 483.4 m, EG Vein (WKP144A) - 5.5 m @ 24.1 g/t Au from 623.6 m, EG Vein (WKP124N) - 6.4 m @ 19.1 g/t Au from 470.7 m, EG Vein (WKP144C) - 5.4 m @ 6.6 g/t Au from 443.5 m, EG HW Veins (WKP144B) - 2.5 m @ 10.3 g/t Au from 436.9 m, EG HW Veins (WKP144B)

Gerard Bond, President and CEO of OceanaGold, said "Today's drill results from Wharekirauponga continue to demonstrate the upside of this exceptional orebody. Drilling indicates a newly emerging high-grade zone that sits outside of reserves, at the southern extent of the known deposit. Importantly, the newly defined high-grade zone is located closer to the planned underground access. With Wharekirauponga remaining open in multiple directions, we remain well positioned to drive shareholder value through continued resource growth and conversion as we increase the amount of drilling this year."

Drill results can be viewed in 3D using VRIFY at the following link: https://vrify.com/meetings/recordings/852c6a5b-6fe4-488f-b10f-0ca92c8aae87

Wharekirauponga Drill Results Overview

Since the Company's November 25, 2025 news release, a total of 6 drill holes have been completed and results returned from the EG, hanging wall ("HW") and footwall ("FW") Veins, collectively referred to as the "EG Vein zone" (Figure 1). Notably, drill results in the southern portion of the EG Vein continue to define the emergence of a new high-grade zone that is on the periphery of the Inferred Mineral Resource but sits outside the Mineral Reserves.

East Graben ("EG") Vein

Drilling from site 9 returned multiple wide, high-grade intercepts demonstrating the continuity of the system in the southern area. Results included 14.9 m @ 16.3 g/t Au (WKP144B) and 5.4 m @ 25.8 g/t Au (WKP144A) (Figure 2). These results support increased confidence in the resource model and extend high-grade mineralization up-dip on the southern portion of the resource. The newly defined southern high-grade zone, encompassing seven drill holes (including previously reported holes) averaging above 160 gram metres, currently spans 150 metres in strike. This area remains open in multiple directions and is a target for follow-up drilling later this year.

At drill site 8, conversion drilling results were above expectations, including 5.5 m @ 24.1 g/t Au (WKP124N). While previous interpretations suggested that the upper extent of the EG Vein was geometrically constrained, new results suggest that the mineralization is dipping more shallowly than previously interpreted and there remains the potential for further up-dip extensions of the EG Vein (Figure 3). Follow-up drilling is also planned for this area.

Hanging Wall and Footwall Veins

The HW and FW Veins and associated extensional sub-parallel structures that lie immediately to the east and west, respectively, of the EG Vein also yielded strong results. WKP144-series (A,B,C) holes returned high-grade mineralization including 5.4 m @ 6.6 g/t Au (WKP144B) and 2.5 m @ 10.3 g/t Au (WKP144B) (Figure 4). These results highlight a zone of high-grade mineralization outside of the current resource model that are largely unconstrained due to limited drilling, yet lies in immediate proximity to the EG Vein and represents a target for future drilling.

Wharekirauponga 2026 Exploration Program

Three drill rigs are operating at drill sites 1, 8, and 9 at Wharekirauponga (Figure 1). We expect to add an additional two drill rigs during the second quarter of 2026 on new drill platforms in accordance with the permit approval in December 2025. Drilling for 2026 will continue to focus on improving resource confidence and further resource growth.