Mr Atkinson - who stressed his views were his own and not those of the Act Party - said the legislation was punitive, populist postulating and didn't work. He didn't believe the heavy sentences it brought about acted as deterrents.
Three strikes took away sentencing options for judges, he said.
The Sentencing and Parole Reform Act 2010 came into force in June 2010, creating a three-stage regime of increasing consequences for repeat serious violent offenders, according to the Ministry of Justice.
There were 40 qualifying offences, comprising all major violent and sexual offences with a maximum penalty of seven years imprisonment or more.
A first warning was issued when an offender aged 18 or over who did not have any previous warnings, was convicted of a qualifying offence. Once an offender had received a first strike warning, it stayed on their record forever, according to the ministry.
If an offender was convicted of a second qualifying offence they received a final warning and - if sentenced to imprisonment - would serve the sentence in full without the possibility of parole.
On conviction of a third qualifying offence the court must impose the maximum penalty for the offence. The court must also order the sentence be served without parole, unless the court considered it would be manifestly unjust, according to the ministry.