An attempt to re-enter the Pike River mine is planned for tomorrow, families confirm.
Earlier this month, the plan to re-enter the access tunnel - known as the drift - was called off after high levels of oxygen were detected, making entering the tunnel potentially unsafe.
At the time, Minister Responsible for Pike River Re-entry Andrew Little said there were elevated oxygen levels that needed to be explained.
"Yesterday unexpected and unexplained readings were reported by the atmospheric monitoring systems in the Pike River mine, leading to re-entry operations being suspended," Mr Little said.
"The safety first approach means that if we can't explain that change in atmostpheric conditions then we suspend operations," he said.
Pike River Recovery Agency (PRRA) chief operating officer Dinghy Pattinson later confirmed one of the sampling tubes that monitored the atmosphere inside the mine had leaked.
But today a spokesperson for some of the Pike River families, Sonya Rockhouse, confirmed that a re-entry attempt will be made tomorrow.
Prime Minister Jacinda Ardern said the government would leave the announcement re-entry for families up to the Pike River Recovery Agency to handle.
"At the families' request, it won't be a public event but one where families will be kept informed and close to that moment."
She would not be drawn on whether the re-entry would in fact go ahead tomorrow.
"The message I gave to the [re-entry] agency was that they understood that safety was the number one priority. I was given an update on the particular issue that occurred a few weeks ago, but ultimately it was for them to manage the exact point at which they completed the re-entry."
She was asked who made the decision not publicise the next attempt at re-entry and to exclude the media.
"It just seemed to make sense to all involved, and certainly the feedback from families was that an intimate event seemed appropriate."
Photos of the re-entry will be released.
No government ministers will travel to the West Coast tomorrow.
What happened at Pike River?
The West Coast coal mine exploded in 2010, with 29 men dead inside.
The incident, investigations that followed and the planned re-entry has been fraught.
In August last year, a police investigation was launched into claims that a second explosion in the mine, five days after the initial one, was triggered by a conveyor belt heading into the mine being turned on.
On 4 May this year, Detective Superintendent Peter Read said the investigation found no evidence anyone entered the hut where the belt was operated from, which was monitored by CCTV.
Mr Read said there was also no evidence the air around the conveyor belt or its electrical systems was anything other than fresh air, and therefore not an explosive mixture of gas.
He said a proposal to start the belt in the days following the first explosion was never supported or approved and there was no evidence the police or anyone else gave authority for the belt to be started.
In March, the leading spokesperson for a group representing victims of the Pike River mine disaster has quit over requests to sign a confidentiality agreement.
PRRA works in partnership with Pike River Families Reference Group, which has created a confidentiality agreement to ensure officials will trust them with sensitive information.
The group acts as a conduit between the families of the 29 men who died in 2010, and police and officials leading the re-entry effort.
The members were not forced to sign the agreement but did so voluntarily.
At the time, spokesperson Bernie Monk said some of the families he represented were upset they might be excluded from information.
Although he had originally signed the document, Mr Monk said he changed his mind after talking with the families.
"I think that just to sign into things and be muzzled, whether it's a memorandum or confidentiality [agreement] or whatever, I just don't want to be a part of that so I just walked away."
Support for re-entry is divided among the community, with some wanting closure for families and others thinking the risk of the process is too great.