WorkSafe has voiced its opposition to dismissing the charges against the owners of Whakaari/White Island.
The directors of Whakaari Management Limited (WML), Andrew, Peter and James Buttle, face charges that allege they made health and safety failings in the lead up to the 2019 eruption in which 22 people died.
It is the third time the brothers have applied to have their charges dismissed.
In his submission on Thursday, their lawyer James Cairney said the brothers should not be facing charges as individuals as it is the company's actions that were investigated.
But on Friday, WorkSafe's lawyer Michael Hodge said the alleged failures of the company were because of failings by each of the three brothers.
"While this is an omissions case ... the core failing alleged against the Buttles is a failure to obtain expert advice.
"Each of the Buttles, through admissions made at interview, conceded that they did not ensure WML obtained a risk assessment."
Cairney had argued WorkSafe did not investigate the three defendants' roles and responsibilities.
But Hodge said it is not the type of omissions case that requires it to.
"The allegation is not that the Buttles failed to do everything reasonable. Rather, the allegation is that each of the Buttles failed to do a specific thing, namely to ensure that WML had and used resources, by failing to obtain expert advice on how WML could ensure that guided tours of Whakaari were conducted safely."
Cairney said on Thursday there were "two key faults" to WorkSafe's case.
First, that it has treated the Buttles as "one group" and secondly, that it sought to treat any breach by WML as a breach by its directors
WorkSafe rejects both of those claims.
"While the court does of course need to consider the evidence against each defendant and reach a separate verdict in respect of each, there is a significant overlap in respect of the allegations and evidence against each Buttle," Hodge said.
"While necessarily related, the allegations against the Buttles are separate and distinct from the allegations against WML.
"In a closely-held family company such as WML, it is unsurprising that there would be a close connection between allegations against the company and the directors."
Hodge referred to an interview with WML in September 2020, attended by Andrew, James and Peter.
"All three spoke on behalf of WML, which they confirmed they were authorised to do in their capacity as directors of WML. All three heard the answers given by the others and had the opportunity to interject if they did not agree with an answer that was given by one of the others on behalf of WML.
"Whilst a PCBU interview would not ordinarily be admissible against individuals speaking on behalf of the company, in this case, the Buttles adopted this statement as their own thereby rendering it admissible against them as individuals.
"The Buttles have also confirmed that they do not oppose the admissibility of the interview for the purposes of this application."
Cairney rebutted that WorkSafe did not address individual roles of the defendants.
"Nothing in this interview goes to the individual circumstances."
He said the interview is company statements and directors can speak on behalf of a company but it does not go to what that person's role is in the company.
Hodge said WorkSafe sent a letter to each of them requesting a voluntary interview, to which they declined.
Reading from the letter WorkSafe received in reply, Hodge read: "They therefore are not aware of any additional information beyond which they provided at the prior interviews which they could further provide. They have adopted the answers already given."
Judge Evangelos Thomas will deliver his decision on Tuesday.