Family members of victims who died in the 2011 CTV Building collapse have accused New Zealand's professional engineering body of "the worst example of double standards" after punishing one of the building's designers while dropping disciplinary action against his boss.

A judicial hearing at the High Court in Wellington began this morning to determine if Engineering New Zealand, formerly the Institution of Professional Engineers (Ipenz), should have pursued proceedings against Dr Alan Reay.

Reay's company Alan Reay Consultants was responsible for designing the six-storey Christchurch office block that collapsed in the February 22, 2011 earthquake that killed 115 people.

A Royal Commission of Inquiry into the Canterbury earthquakes criticised Reay for giving his inexperienced structural engineer David Harding "sole responsibility" for the building's mid-1980s design.

Professor Maan Alkaisi, whose wife Maysoon Abbas died in the collapse, this morning accused Ipenz of "the worst example of double standards" by punishing Harding but not taking any action against Reay.

"This was in spite of the fact that both were members of Ipenz, both resigned before the disciplinary action, and both had the same responsibilities in the design of the CTV Building," said Alkaisi, spokesman for the CTV Families Group.

"Not only is this hearing about accountability but it is also about public safety – the need to send a strong message to the construction industry and practising engineers."

The chief engineer for Ministry of Business, Innovation and Employment (MBIE) made a complaint to Ipenz about Reay's involvement in the CTV Building in 2012.

But Reay resigned his voluntary membership of the institute in February 2014 while the professional body was investigating the complaint and later decided not to pursue any disciplinary action against him. Ipenz concluded it no longer had jurisdiction to deal with a former member.

A September 2014 decision by the High Court relating to Harding ruled that an investigation and disciplinary hearing could continue even when a member resigned.

Last year, a long-awaited police probe concluded that no criminal charges would be laid despite "significant" design deficiencies.

In 2015, the Attorney-General filed for a judicial review of the Ipenz decision.

"It is important that we clarify the law as to whether a professional can avoid disciplinary proceedings by simply resigning," then Building and Housing Minister Dr Nick Smith said in March 2015.

"Completing the Ipenz investigation will also be important in clarifying the professional standards expected of a senior engineer supervising the work of a more junior engineer,"

The Attorney-General is seeking the Ipenz decision to be overturned and for Engineering New Zealand to complete the investigation into the professional conduct of Reay's role in the design of the CTV Building.

Engineering New Zealand says it will abide by whatever decision the court makes.

Alkaisi said the CTV Families Group will continue to "stand up for what is right" and "stay true to our heart's pursuit for accountability and justice".

"The tragedy of the CTV Building collapse, which resulted in one of the most tragic and unnecessary losses of life in the history of New Zealand, will always be linked with building and engineering design and safety.

"After almost eight years since the CTV tragedy no one has been held to account and there has been no closure for the families who lost loved ones – no accountability, no justice.

"For as long as the case of the CTV Building collapse remains unresolved, we CTV families will remain determined to persevere in our pursuit for justice."

The judicial review hearing is set down for three days.