"They want to know the truth about what happened to their loved ones on 16 August. They want the opportunity to see the evidence unfold," Seri said in a statement on Sunday.
"They particularly want to see and hear for themselves what the police have to say about their conduct."
Seri has been instructed to represent the Association of Mineworkers and Construction Union (Amcu) and 21 families of people who were killed by the police on August 16 at the Farlam commission of inquiry.
The justice department said on Saturday that it would no longer provide funding for the families to attend the commission hearings in Rustenburg.
Seri said it was "shocked and appalled" at the decision by the department to suspend the funding.
"The decision was taken without prior notice or consultation. Our clients are distraught."
In its statement on Saturday, the justice department said some of the families said they would rather have the travel money paid to them directly as they were struggling due to the loss of their breadwinners.
Seri said this was "grossly misleading" and denied that their clients had told the department they did not want to travel to the hearings.
"They very much wish to do so. They are deeply upset that the department has, at the eleventh hour, decided that they will not be assisted to attend the commission's hearings when it reconvenes on October 29," the organisation said.
Seri said the suggestion by the department that the families were choosing between travel funding or financial assistance for daily necessities was also misleading.
"The truth is that the department of justice is not willing to assist our clients at all – either to attend the commission, or to feed their families," the organisation said.
"Its decision to withdraw its support is immoral and, in our view, unlawful."
The department had helped pay the travel costs of the families to attend the first session of the inquiry but financing further attendance would be left to the families themselves.
Many of the families of victims are not from North West but other provinces such as the Eastern Cape.
No legal obligation
"The attendance of the first session of the commission was mainly based on humanitarian basis as it is important that they understand the primary purpose of the inquiry," said department spokesperson Mthunzi Mhaga said on Saturday.
"Further attendance of the inquiry would be left to the choice of the families themselves."
He said the department could not continue funding the travel of family members to attend the commission because it was under no legal obligation.
"In as much as we are sympathetic to the families and understand their desire to attend the proceedings, we cannot finance their attendance as that is not covered by any legislative framework that governs the work of the commission," Mhaga said.
"Regulations applicable to the commission make provision for legal assistance to be afforded to any such witness whose evidence may be relevant to the terms of reference of the commission, and families will be entitled to same assistance if they participate as witnesses."
Mhaga said to the Mail & Guardian on Saturday: "It has never happened in the history of South Africa that the department has paid for family members to watch hearing proceedings. So why are we being vilified for doing this?"
If family members were called as witnesses to the commission their travel expenses would be covered. – Additional reporting by Sapa