And claims have also emerged that police have instructed officers to head directly to any roadblocks established immediately - and not leave there, even if an urgent call for help has been made.
The latest police slip-up followed police apologising for supporting a block on an NZME journalist with essential worker documentation travelling on State Highway 1 north of Houhora.
Having apologised for that, police were also then forced to admit the officer meant to be on the checkpoint had been called away for 70 minutes on an urgent job. It was a backtrack on a senior commander's claim the officer was present, just not in the journalist's "eyesight".
This morning, Coster was quizzed by Hosking over the roadblock.
During the interview, Coster said: "It is probably fair to say it is not lawful to be stopping cars without a police presence."
But he then said: "It was a line call in the case of that particular journalist. He is Auckland-based. Most journalists are managing to do their business using video. He was hours and hours from his home location and providing very limited detail."
The statement was wrong. Police were told on Friday the journalist was Far North-based and was operating inside his home region. The officer who turned up at the checkpoint was also told the journalist was local.
The "limited detail" appears to be a reference to a request at the roadblock for details of the journalist's intended work schedule. Those at the roadblock were told it was not their role to decide whether intended news stories were valid or not.
Police have not responded to a request for comment on Coster's claims to Hosking.
The roadblock was set up by Ngati Kuri, manawhenua of the land from roughly north of Houhora Harbour. It was set up at the outset of the level 4 lockdown to stop people heading into an area with higher numbers of Maori and people in poverty than other areas - both factors in higher epidemic mortality rates.
Entry to the area was refused to all, even those iwi members who attempted to enter from outside the Far North, in a bid to keep out the virus.
There has been growing controversy over roadblocks as the country moved from level 4 to level 3 with an increase in movement.
The incident at the Ngataki roadblock was striking because it came a day after Coster had testified at the epidemic response committee, saying no one was being stopped travelling on state highways and that every "checkpoint" had a police presence.
In the interview with Hosking, Coster said the number of roadblocks had been reduced from around 50 to seven and he expected the number to further reduce to zero.
Northland MP Matt King said he had learned police were now being told to stay at "checkpoints", even if an emergency occurred nearby. He said it was an unnecessary restriction on police resources.
King said the instruction had come from Northland police leadership and would be an "operational nightmare" in a region where there was often only a single police officer responsible for a large geographical area.
"Sometimes police need to attend multiple emergencies a day but, instead of being able to attend those urgent emergencies, police officers are now required to stay at community checkpoints.