Papua New Guinea's Minister of Petroleum and Energy says the full extent of the country's resources is still largely unknown.
William Duma's comment comes amid increasing investment in PNG's energy sector by major global players.
Mitsubishi has just entered into a joint venture to develop leases held by Canada's Talisman Energy in Western Province for potential gas exports.
Exxon Mobil is already leading a major liquefied natural gas project in PNG.
And this month, Shell announced it's setting up an office in Port Moresby to further its alliance with the state energy company, Petromin.
Mr Duma says PNG welcomes more major players.
"Compared to other countries in the region, we are relatively under-explored. There's a lot of areas that still need to be explored. There's a lot of seismic work that needs to be done. We are all now concentrating on onshore acreages. We have not moved even to offshore acreages. So we are virgin territory in terms of exploration."