Yet another chink has been exposed in Australia’s quarantine system, as New South Wales promises to again tighten its rules for international arrivals after two visitors were allowed to hop on a flight to Melbourne.

NSW Police admitted an officer wrongly allowed the German pair to skip quarantine, blaming a “language barrier” for the error.

The state Labor opposition wants assurances the breach can’t be repeated.

“Quarantine needs to be a fortress, but a fortress only works if you don’t leave the front door open,” Labor health spokesman Ryan Park said.

The two passengers – a 53-year-old woman and her 15-year-old son – arrived from Germany via Japan on Saturday, but did not go into the mandatory quarantine period in NSW.

They flew into Sydney aboard a Japanese airline, then took a Virgin Australia flight to Melbourne, before the error was realised.

The pair flew on Virgin Australia to Melbourne. Photo: ABC News

The New Daily understands part of the issue was the Germans had been given all boarding passes, and were checked in to all legs of their trip, before leaving Europe.

This is not normal procedure, according to Virgin Australia, and meant they would have avoided Virgin’s pre-flight check-in procedures, which screen passengers for recent overseas travel.

The alarm was only raised in Melbourne when an airport employee there realised the pair should have been placed into quarantine.

They are now the first people in Victoria’s refreshed hotel quarantine system.

The entire VA838 flight from Sydney to Melbourne has been told to self-isolate at home, and the plane is being deep cleaned.

Policeman made quarantine error

Questions were immediately raised as to how the pair were allowed to skip quarantine.

Late on Sunday, NSW Police admitted an officer who was new to the airport system had mistakenly allowed them to avoid going to a hotel, with police escorting them between the international and domestic terminals.

Police deputy commissioner Jeff Loy apologised, blaming a “language barrier” and “communication issues” for the mix up.

“It’s not a good look,” he admitted.

The mistake happened during what was the officer’s second shift on the airport operation, Mr Loy said.

Jeff Loy admitted police made errors in quarantine. Photo: AAP

It’s the latest bungle in quarantine measures for international arrivals, following a NSW hotel employee contracting COVID from visiting American pilots last week, Adelaide hotel workers spreading the virus to others through their second jobs in hospitality, and well-documented issues in Melbourne’s system.

Acting chief medical officer, Professor Paul Kelly, said last month hotel quarantine was the “major risk now of reintroduction of COVID-19” into Australia.

Infectious disease experts warned the system “has to get better”.

Mr Loy said the officer involved was “very remorseful” and a “very fine officer” who mistakenly believed the German pair had an exemption to let them skip quarantine.

He added there was no suggestion the arrivals had lied to police, and no charges would be laid.

The deputy commissioner said the broader operation, which had seen some 100,000 arrivals placed into quarantine in NSW, had been an “outstanding” success.

“Is it fail-safe? Obviously not,” Mr Loy admitted.

Police will beef up their procedures at Sydney airport, with the deputy commissioner saying only senior officers would be allowed to review quarantine exemptions.

Thx to @nswpolice 4 incredible work every individual officer has done to keep NSW safe in this 1 in 100 yr pandemic @NSWHealth & @AusBorderForce & Aus Defence Force members have all worked in partnership with police. But it is a human system & is not infallible.

— Brad Hazzard (@BradHazzard) December 6, 2020

NSW Health Minister Brad Hazzard tweeted “it is a human system & is not infallible”, in praising police and other agencies involved in the quarantine system.

‘We can’t afford another Ruby Princess’

But his Labor counterpart Mr Park wants answers over the Sydney flub.

“I’m very concerned that there has been yet another breach in our quarantine arrangements. Effective quarantine of overseas arrivals is our strongest weapon against a second wave in NSW,” Mr Park said.

“We can’t afford another Ruby Princess fiasco where arrivals with COVID are sent off into the community. There needs to be a full investigation so the community can understand how it happened and what steps will be taken to ensure it never happens again.”

Virgin Australia said it was concerned about the quarantine breach, with a spokeswoman distancing the airline from the mistake.

Health Minister Brad Hazzard said the quarantine system is “not infallible”. Photo: AAP

“We have contacted NSW Health to determine how these passengers were able to enter the country without going into hotel quarantine,” she told TND.

Virgin said its own check-in procedures include an extensive questionnaire asking passengers to assert their recent movements and health information, which would have picked up the pair’s recent arrival into Australia.

It appears those checks did not take place because the passengers, who flew the main leg on a Japanese airline, were checked in for all flights before leaving their home country.

Victorian Premier Daniel Andrews praised the Melbourne airport employee who had picked up the quarantine error, saying they had done an “amazing job”.

“We are very grateful to them and hopefully they are suitably honoured by their employer and if they don’t, we certainly will,” the Premier said on Sunday.