Contractors say the country has a right to know there were delays in responding to the first explosion at the Pike River mine.
Twenty-nine men were killed in a series of explosions that began at the West Coast mine on 19 November last year. Only two men, Daniel Rockhouse and Russell Smith, managed to walk out of the mine.
The mine was placed into receivership in December last year and former contractors owed $5 million are applying to the courts to have Pike River Coal Ltd liquidated.
In submissions contractors are to present to the Royal Commission, they claim it took 51 minutes before emergency services were called to the mine after the initial blast.
Contractors also claim that Pike River Coal initially did not know how many workers were underground.
The information is based on a series of interviews carried out by the Pike Rivers Contractors and Suppliers Group and made available to a business meeting of 90 people in Lower Hutt on Monday.
Group says facts disturbing
The group's chairperson, Peter Haddock, told Radio New Zealand's Morning Report programme the facts are disturbing.
"There's a lot of unanswered questions - especially the delays and how no one was there to meet Daniel and Russell when they came out of the mine. It's continually upsetting for people to not know the truth - and I guess that's all people want to know is the truth."
The group says information it has about the mistakes made after the initial explosion cannot be disputed and it will be presented under oath to the Royal Commission.
It says the public needs to know what happened now and should not have to wait for the Royal Commission - which might not be effective anyway.
Neville Rockhouse, a safety and training manager at the mine, says the Royal Commission needs to address the group's claims.
Mr Rockhouse was in the control room managing the unfolding disaster, but was not told of a call for help from his son Daniel from within the mine. His other son Ben died.
Mr Rockhouse told Morning Report if he had known of the call, someone would have been at the entrance to meet the two survivors. However, he is not convinced that entering the mine would have been the best move, as some have claimed.
"We have real time monitoring and if you had've sent them down at that time when our gas monitoring system had been blown to bits with the initial explosion, you could have a situation like looking down the barrel of a gun with someone who's got their finger on the trigger."
Mayor says mistakes were made
Grey District mayor Tony Kokshoorn says the claims are valid, and there were delays and mistakes made.
However, Mr Kokshoorn told Morning Report it is understandable that the company initially did not know how many miners were underground.
He says some miners' tags, which should be have been returned to hooks at the end of the previous shift, were not there.
Police say the contractors' comments are not new and it is unfortunate they are being made at this time.
An international mine safety expert, Dave Feickert says mine safety standards are a chaotic mess.
He says New Zealand was wrong to get rid of its professional mines inspectorate while best practice in Australia and Europe was strengthened.