The ABC’s 7.30 on Tuesday night revealed fresh details about the latest illegal boat arrival — understood to be the third to land on Australian soil in under six months — when 15 people were found at the remote Mungalalu-Truscott Airbase in the far north Kimberley region of Western Australia on the afternoon of April 5.

Several of the men entered the unfenced commercial air base undetected and alerted staff, according to the report, raising fresh questions from locals about the lapse in security.

“I think the main thought on everyone’s mind is, ‘How on earth did this happen?’” Matthew Niikkula from the North West Defence Alliance, which represents the seven local governments in the area, told 7.30.

“If a random boat can arrive and people into an air base, what else is happening in the north? The most vulnerable coastline we have is along the north, so this shows that we need to see a focus of key assets, key infrastructure and a lot more of a defence presence.”

In December, the Australian Defence Force (ADF) began using the air base “in support of Operation Sovereign Borders” as a staging ground for unmanned military drones patrolling the coast.

The Chinese nationals were flown to an offshore detention centre in Nauru shortly after they arrived.

One of the men claimed they were economic migrants, according to 7.30, which said there was no suggestion they had any malicious intent entering the air base.

Madeline Gallagher-Dann from the Kalumburu Aboriginal community, the nearest settlement 35 kilometres southeast of the air base and home to about 400 people, said it was “pretty scary thinking they got this far and made it to land not far from us”.

“[Border protection] could definitely be done a bit better because we’re vulnerable — we’re open and there is no patrols on this side,” she told 7.30.

The Australian Border Force (ABF) said in a statement it was “adequately resourced and prepared” to respond to security threats.

“A combination of Australian Defence Force and ABF aerial and maritime assets are always postured to detect and intercept maritime people smuggling ventures in Australia’s key maritime threat corridors,” read the statement to 7.30.

“In 2023-24, additional assets were deployed to support the posture. The ABF does not go into specifics about capability assessments and requirements, other than to say that we are adequately resourced and prepared to address … maritime security threats.”

2GB host Ben Fordham said the revelations were “extremely concerning”.

“It’s border failure, that’s what it is,” he told listeners on Thursday.

“We’ve had boats dropping people off like they’re Uber passengers, and now we have this Chinese delivery, and they don’t seem to fear Operation Sovereign Borders under Anthony Albanese.”

The ABF has been contacted for further comment.

In February, a boat carrying two groups of 39 Pakistani and Bangladeshi foreign nationals were found on the Dampier Peninsula north of Broome.

In November last year, another group of 12 illegal arrivals slipped past naval border forces and reached the Truscott-Mungalalu Airbase.

In both incidents, they were intercepted by the ABF, and taken to Nauru.

There has also been a large increase in the number of illegal foreign fishing boats intercepted by the ABF off the Kimberley coast in recent months.

Following the April 5 incident, Prime Minister Anthony Albanese said that he had sent a “very clear message” that illegal boat arrivals would not be accepted into Australia.

“We have a very large coastline,” he told reporters.

“What is clear, though, is that people who are unauthorised arrivals will not be settled in Australia. Operation Sovereign Borders principles will apply as they have been in this case.”

But Opposition Home Affairs spokesman James Paterson described the situation as a “failure” and claimed the arrival would incentivise people smugglers to attempt to enter Australia.

“Aerial surveillance hours under this government’s watch have dropped 20 per cent, maritime patrol days have dropped 12 per cent, and the result of that is people are getting through, they are getting onshore, and our border protection regime is being undermined,” he said.

“It’s no surprise that people smugglers are testing [the government’s] will.”

Senator Paterson told ABC News that Labor’s abolition of temporary protection visas provided an incentive for people to “get on boats and come here”.

“The abolition of that visa by this government has sent the wrong message to people smugglers and would-be asylum seekers, and regretfully appears to have encouraged them to get on boats again and the reason why that’s such a problem is we know last time, that cost at least 1200 lives at sea,” he said.

“We don’t want to see that happen again. We don’t want to see people drowning on unseaworthy vessels on the way to Australia … we’re about to see that again.”

Labor abolished the TPV and the Safe Haven Enterprise Visas in February 2023, opening up a path to permanency for thousands of refugees who arrived prior to Operation Sovereign Borders’ establishment in 2013.

Senator Paterson said he was “very concerned” that the government appeared to be slashing the border force budget, instead of increasing it.

The government has routinely denied the claim, with Environment Minister Tanya Plibersek spruiking the $500 million extra given to Operation Sovereign Borders under Labor.

“Of course, we don’t like to see boats arrive and these people have been dealt with immediately,” she told Channel 7 earlier this month.

“It sends a strong message to smugglers who might consider sending people on this terrible, dangerous journey. The commander of Operation Sovereign Borders has made it clear that nothing has changed [with the border policy] … that the settings are as strong as ever, and they have got the extra budget now.”

— with NCA NewsWire