Business magnate Owen Glenn spoke perceptively last week of how New Zealand was living beyond its means and had to decide how it was going to pay its way.

One way for the country to earn its keep, he said, was to make greater use of its mineral wealth. That message has a particular relevance at the moment, not least to those protesting against Brazilian company Petrobras' search for oil in the Raukumara Basin off East Cape.

Rather than spread alarm about the exploration programme, they would do better to consider the economic benefits of a big strike.

That is a long way off. For now, a Petrobras vessel has begun seismic testing. Data gathered seven years ago indicates there are sediments and sands in the area able to trap hydrocarbons in commercial quantities. But, as with so much of the water off New Zealand, the area is largely untested.

This country, as much as Petrobras, needs to know what is there. Once the company's preliminary testing is completed, by May next year, it will decide to do more testing or surrender its licence. Any verdict on the area's commercial viability, the precursor to full drilling, is probably years away.

Yet listening to the protesters, you would imagine deepwater drilling is about to begin the day after tomorrow. Even the well-established and standard practice of seismic testing has suddenly become a serious environmental hazard. But most of their powder has, of course, been reserved for the potential for a deepwater well in the Raukumara Basin to share the fate of the Deepwater Horizon rig in the Gulf of Mexico.

Undoubtedly, it was unfortunate that Petrobras' five-year prospecting permit was awarded at virtually the same time last year as the impact of BP's massive oil spill became apparent. Equally, it is true that the risk of such episodes has increased as explorers probe deeper and deeper waters in their quest to sate the ongoing global thirst for oil. But it makes no sense to rule out exploration in New Zealand waters because of an accident on one of the multitude of rigs worldwide, no matter how calamitous that may have been.

The rest of the world has now placed the Deepwater Horizon accident in context. Britain, for example, has accelerated deep-sea exploration off the Shetland Islands. This country has too much at stake to step back. Indeed, it needs Petrobras to succeed, given the results of drilling over the past couple of years have not been as encouraging as hoped. Most damagingly, ExxonMobil has withdrawn from the Great South Basin. In many ways, the presence of Petrobras, one of the world's top 10 oil and gas companies, is a much-needed vote of confidence.

That is not to say New Zealand should ignore the lessons of the Gulf of Mexico. A far smaller spill here would have devastating consequences for the fishing and tourism industries, and for the country's clean green image. But there is time enough before deepwater drilling starts, if, indeed, that happens off the East Cape, to ensure New Zealand has rules that ensure it is adequately prepared. A Government-ordered review of those rules will play a key role in this, as will the new Environmental Protection Agency, a product of the Government's resource management reform.

New Zealand needs a big oil discovery to show it has proven large reserves. That, combined with its attractive exploration regime, would entice other major explorers to come here. The potential benefit in tax and royalty income, jobs and regional development is enormous. If there is, as with virtually any activity, a risk, there is also the prospect of huge reward. It is not a possibility the country, including those protesting against Petrobras' presence, can afford to pass up.