New Zealand may see more large energy explorers in future.
Deloitte analyst Paul Callow says the Brazilian company Petrobras is likely to be one of a growing number of foreign-backed explorers hoping to tap into New Zealand's energy resources.
Mr Callow says any significant finds could help to stabilise electricity prices, and boost investment in renewable energy.
Petrobras has won the sole right to explore and drill for five years in the Raukumara basin off the East Cape.
It is partly owned by the Brazilian government, and Mr Callow says national oil companies are generally much larger than the oil giants such as BP, Shell and ExxonMobil.
He says there is also a global trend for state-backed companies to look further afield for gas and oil prospects.