Greens call on environment minister Greg Hunt to resign after breaking numerous pledges to send a boat to monitor the whaling season

The Coalition has been accused of breaking an election promise by announcing it will send an aircraft, rather than a ship, to monitor Japanese whaling activity in the Southern Ocean.

The environment minister, Greg Hunt, said on Sunday an A319 aircraft, co-ordinated and staffed by Customs personnel, would be deployed for the monitoring from January to March. The Greens have called on Hunt to resign over the decision, which they describe as “weak” and a clear breach of an election promise.

Hunt has come under pressure to move quickly to fulfil an election pledge to monitor the Japanese fleet, which is closing in on Antarctic waters claimed by Australia.

Hunt said the aircraft would monitor activities by “all groups in the Southern Ocean”, a reference to a trio of Sea Shepherd anti-whaling vessels already dispatched to the Southern Ocean to confront the Japanese.

But he made no mention of how vessels illegally fishing in Australian waters would be intercepted or turned around, nor how a plane would react to prevent loss of life in the event of a violent clash between whalers and Sea Shepherd activists.

“It is important for Australia to have a monitoring presence in the Southern Ocean given the risk of confrontation between whalers and protestors,” he said. “While we respect the right to peaceful protest, Australia will not condone any dangerous, reckless or unlawful behaviour.”

Hunt said a plane, rather than boat, would be used due to “operational reasons”, claiming that the government has fulfilled its election pledge to introduce whaling monitoring for the first time since 2008.

“The aircraft will be able to monitor activities over a large area,” he said. “It sends a clear message that the Australian government expects all parties to abide by the laws of the sea.”

The Greens say Hunt has broken his election promise by failing to send a ship, which he urged Labor to do in writing on three occasions when the Coalition was in opposition.

In February, Hunt said Australia “should have a Customs vessel in the Southern Ocean”. In April, he said “there is an entire division of Customs meant to be conducting Southern Ocean patrols”, adding the Coalition “would make sure it is operational down there during the whaling season”.

In August, Hunt said the Coalition “commits to sending a Customs vessel to the Southern Ocean”, should the whaling season continue.

Among its list of policies released before the election, the Coalition said it would ensure resources “devoted to patrolling illegal foreign fishing are not diverted to other activities”.

“This includes ensuring the ACV Ocean Protector and/or its replacement is provided with sufficient funding to devote an adequate level of patrol days in southern waters every financial year,” the fisheries policy said.

The Ocean Protector, which is custom-built to patrol the Southern Ocean, is being used as part of Operation Sovereign Borders to intercept asylum-seeker boats near Christmas Island. Hunt appears to have lost claim over the boat to his cabinet colleague Scott Morrison, the immigration minister.

“This is bitterly disappointing as Greg Hunt was clear in his rhetoric that a Customs vessel should be sent,” Greens senator Peter Whish-Wilson said.

“This is a quick fix in a weak attempt to show he is holding up an election promise. Frankly, this is why people are so sick of politics in this country – you see someone so outspoken on whales for so long and when he has a chance to make a difference, he fails at the first post.

“I don’t think he’s been lying for the past six years on this, he has clearly been rolled by his cabinet colleagues. If he has any guts, he would resign. He should resign to help himself sleep at night.”

Australia is locked in an International Court of Justice dispute with Japan over whaling activity. The government had been hoping for a ruling before the Japanese fleet departed for the whale sanctuary.