Humpback whales at Port Stephens.

A humpback whale at Port Stephens. Photo: Richie McCormack

Four months ago, I looked into the eyes of a huge yet gentle humpback whale.

We were in Tonga, on a photographic trip, snorkelling near a mother humpback and her playful calf. I detached myself from my group to return to our boat but, to my amazement, mum followed me.

Gently, slowly, she eased her way through the water until we were nose to nose, leaving no more than a couple of metres between us. Just as I thought we'd collide, she suddenly stopped.

Her eyes searched mine, and we looked intently at each other for what seemed an age. Then, almost imperceptibly at first, she arched her back slightly and dipped beneath me, her stubby dorsal fin almost brushing as she and her calf glided past into the deep. So smooth was her movement that the water wasn't even disturbed.

Soon mother and calf would be heading south, to the krill-rich waters of the Southern Ocean and Antarctica, sharing their endless migration with thousands of their kind.

Having been looked in the eye by a humpback, it's impossible to stand by idly as the latest Southern Ocean whaling season begins. If they are there now, my mother and calf may encounter humans who are not harmless tourists: the Japanese whalers bent on killing them, ostensibly in the name of science, while upholding spurious national honour in the face of global condemnation.

Despite a challenge now before the International Court of Justice, Japan continues to insist on slaughtering humpback, minke and southern right whales, dismissing international outrage over its policy.

As in previous years, this summer Japanese whalers will be confronted by vessels of the radical activist organisation Sea Shepherd, now en route to the whaling zone.

I believe Sea Shepherd protesters have a just cause, but that their vigilante methods are wrong. They take reckless and often violent actions that provoke ugly and dangerous confrontations to disrupt the whalers and maximise media coverage. The Japanese whalers retaliate in kind. Ships and property on both sides are damaged but, worse, people are injured and, before long, could be killed.

What's really needed in those cold, unforgiving waters is the rule of law, backed by a respected presence. The Australian government has the resources to do this.

The Australian Customs Service has a 105-metre vessel, the Ocean Protector, specifically fitted out for deep-water fisheries patrol. Its intended role is upholding Australia's Southern Ocean economic interests, especially the prevention of illegal fishing affecting the Australian economic exclusion zones around Heard and Macquarie Islands. It also can assist other countries with adjoining economic rights.

The Ocean Protector therefore can protect Australia's interests regarding the operations of Japanese whalers and help keep the peace between whalers and Sea Shepherd activists bent on confrontation. But this summer it will be in warm Indian Ocean waters, deployed against people smugglers for Operation Sovereign Borders.

Instead, Environment Minister Greg Hunt announced last Sunday that, from January to March, a long-range Airbus A-319 aircraft will fly over the whaling zone. Hunt confirmed there will be no official sea-level presence there this season.

While this is Australia's first such presence of any kind since 2008, the Abbott government's decision sets aside an election Coalition promise to ''ensure that resources devoted to patrolling illegal foreign fishing are not diverted to other activities. This includes ensuring that the Ocean Protector is provided with sufficient funding to devote an adequate level of patrol days in southern waters every financial year.'' In the Ocean Protector's absence, there's not just a risk of slaughter of the great whales of the Southern Ocean, there's a real risk of collision, which could lead to injury or to a loss of life at sea. These aren't my words: Hunt himself rightly said this back in February. The only thing that's changed since is the government.

Hunt defended the new government's breached promise by saying that an aircraft could cover a very large area and many contact points for the whaling fleet, not just one. But, surely, what would be most effective are aircraft and the Ocean Protector operating in tandem in the confrontation zone, their joint presence deterring both whalers and protesters from illegal and dangerous actions. Aeroplanes can't intervene when tempers boil over: the Ocean Protector can.

In these pages in October, I praised Hunt for his passionate anti-whaling stand. To his great credit, he treats whale conservation as a mainstream political matter, and fought for his election promise to be honoured fully. But I worried then that not all Hunt's colleagues share his vision: sadly, I was right.

If the government has gambled that this will upset only hard-core greenies who would never vote Coalition, it's seriously mistaken. The anti-whaling message resonates strongly in middle Australia, too.

Whales in waters under Australian jurisdiction, most likely including my gentle humpback mother and calf, deserve protection from man's destructive hand. This responsibility should not be abdicated by our government to Sea Shepherd vigilantes.

With whalers and protesters likely to start clashing next week, it's already too late to redeploy the Ocean Protector to the Southern Ocean this season. But next year must be different.

Hunt's promise-breaking colleagues should remember that, while whales don't vote, millions of Australians who want them conserved do.

Terry Barnes is a former ministerial adviser to Tony Abbott.