The Department of Labour has laid charges against three parties in connection with the Pike River mine disaster.
Twenty-nine men were killed in gas explosions that began in the West Coast coalmine on 19 November last year.
The department, which has been investigating the disaster for nearly a year, said on Thursday that under the Health and Safety in Employment Act it had laid 25 charges against three parties, alleging health and safety failures at the mine.
Each charge carries a maximum penalty of $250,000.
Neither the names of the parties nor the charges have been made public because of name suppression orders.
Publication expected on Friday
A lawyer for the Pike River families, Nicholas Davison QC, says he expects the names to be made public on Friday.
Mr Davison says the Greymouth district court imposed a blanket suppression on any Labour Department charges earlier this year to help the Royal Commission on the disaster.
With the commission's inquiry beginning again on Monday, he says he expects the department is urgently seeking the lifting of the suppression.
Mr Davison says the people charged might not now be willing to give evidence to the commission, but others not charged will be freer to do so.
Charges make a difference - families
The secretary of the Pike River Families Committee, Carol Rose, says the charges make a difference because they hold some people responsible.
"It's nice to see that the judicial process is progressing," she says, "and that hopefully we'll get some answers and we'll get to the truth of the matter."
Ms Rose adds however that the charges do not help with the real fight of getting the remains of the 29 men out of the mine.
'One of the most complex' investigations
Earlier this year, the Department of Labour's acting deputy chief executive, Lesley Haines, described the department's Pike mine investigation as one of the most complex it had done.
Under the Health and Safety in Employment Act, the department may lay charges any time within six months of an incident; but the act also allows the court to extend that time limit.
The initial six-month period ran out in May and the department sought and gained a six-month extension.