Justice Whata revealed Eruera had nine previous convictions for violence, and was on parole at the time of the murder, and already had a first strike warning.
Judges have discretion to decide to impose the maximum sentence without parole on a second strike warning. It is mandatory to impose the maximum sentence without early parole on a third strike unless it is deemed manifestly unjust to do so.
Eruera had earlier been jailed for injuring a man by driving his car at him, and for bludgeoning two women with a gun.
Mr Hollister-Jones has confirmed to the Bay of Plenty Times Weekend that he would be referring the case to Crown Law for consideration on whether the sentence should be appealed.
"There are two similar Auckland murder cases which are already subject to a Court of Appeal hearing in June," he said.
Mr Hollister-Jones said both other offenders also received life imprisonment sentences with minimum non-parole periods - despite being subject to first strike warnings at time of the murders.
Ministry of Justice data revealed that between 2010 and 2016 there were at least 310 first strikes warning, and eight final warnings issued in Tauranga courts since the legislation was introduced.
That is, one in 2013, two each in 2014 and 2015 and one this year.
No one in the country had so far received a third strike.
In the current case, if Justice Christian Whata had imposed a life sentence without parole, he said it could have seen Eruera serve 30 to 50 years behind bars depending upon his life expectancy.
But, Justice Whata ruled it would be manifestly unjust to do so, given the serious provocation involved which sparked Eruera to launch his two retributory attacks.
Eruera's step-daughter had falsely claimed she had been assaulted by the deceased at the party and attacked by two other men, one of whom attempted to rape her.
Sensible Sentencing Trust spokesman Ken Evans said this case was a shocking state of affairs.
"This guy has a horrendous conviction record and was on parole at the time when he murdered one young man and attacked another. He's had so many previous warnings. How many chances are we going to give these types of offenders before they are handed serious and sensible sentences?
"A judge's job is to protect you and I from these people and they're letting the people of New Zealand down. Once again it seems the sentencing focus is more on the offender rather than the impact on victims and the protection of public at large."
Justice Minister Amy Adams said between June 1, 2010 and February 26, 2016, 6508 first strike warnings and 122 final warnings were issued.
Ms Adams said: "The deterrent effect of the three strikes regimes can only be properly assessed over time."
However, the Government's new measures to track family violence and reoffending rates showed violent crime was trending down, she said.
