Mrs Muliaga, 44, died on May 29, just hours after the electricity to her home and oxygen machine was disconnected by Mercury Energy, the retail arm of state-owned Mighty River Power.
Mrs Muliaga's family have welcomed the decision not to lay criminal charges over her death but may still look at civil proceedings.
Miss Clark said in Melbourne today that she also accepted the police decision but that Mercury Energy had behaved badly
"The police look at criminal responsibility. That is the judgement they make," she said at the commissioning of the navy's new ship, HMNZS Canterbury.
"What the public of New Zealand knows is that Mercury Energy behaved badly and when the Electricity Commission puts out guidelines, companies are expected to follow them, particularly state owned enterprises which have a social responsibility mandate under law."
Counties-Manukau Police said in a brief statement that there was no evidence to justify any charge against Mercury Energy, their contractors or staff members.
Mercury ordered the power to be cut because of an overdue power bill of $168.40.
Mrs Muliaga's death will now be referred to the Auckland Coroner.
The Government was now reviewing the law which directed state owned enterprises to behave in a socially responsibly way.
"It is likely we will want reporting against that (law) in the future," Miss Clark said.
She believed there was provision in the guidelines for social responsibility.
"My understanding is that there hasn't been active reporting against that in the past. That is not to say there hasn't been social responsibility exercised but it has not been actively reported on. That is what we are seeking to change," Miss Clark said.
The Muliaga family had urged that no criminal charges be laid, saying nothing would be achieved by the police investigation into her death and it would be unfair to prosecute the contractor.
"I am not surprised. It's what I expected as a lawyer because of the high standard of proof needed for criminal liability," family lawyer Olinda Woodroffe said.
However, she said the family would be pursuing civil action over Mrs Muliaga's death.
"I'm willing to talk to any parties about settlement. Court would be an absolute last resort."
Ms Woodroffe said the police decision not to prosecute had no impact on the family's complaint over the police treatment of family members during the investigation.
"They are completely separate issues," she said.
Family spokesman Brenden Sheehan said he was pleased for the contractor who cut the supply that police had decided not to prosecute. He said as part of the Muliaga family's healing process, it could move forward knowing no one else would suffer.
Mr Sheehan said the family was waiting for the outcome of the criminal inquiry before pursuing other legal avenues. He said Mr Muliaga was going to have to give up work to look after the children and the family needed to consider its future security.
Mighty River Power chief executive Doug Heffernan said he was pleased at the police decision, but admitted Mrs Muliaga's death had raised important issues and was reviewing the way it dealt with customers with medical dependencies or in financial hardship.
"Mercury Energy is committed to working with government regulatory and welfare agencies to develop improved procedures so we can identify and assist vulnerable customers more effectively."
Who is to blame
Debate has raged throughout New Zealand since her death, as the public and politicians sought to establish who was to blame for the tragedy.