Building Minister Nick Smith says he hasn't been in the job long enough to decide whether disciplinary procedures against engineers need to be strengthened.
The Institution of Professional Engineers New Zealand says it is no longer investigating civil engineer Alan Reay because he is no longer a member. His company Alan Reay Consultants designed Christchurch's fatally flawed CTV building which collapsed in the February 2011 earthquake, killing 115 people.
Ipenz is calling for a change in the law to require chartered engineers to design major buildings and allow non-members to be investigated.
Dr Smith has been the Building Minister for less than two weeks, replacing Maurice Williamson who resigned. He told Radio New Zealand's Checkpoint programme on Tuesday he wants to consult further with the sector before deciding whether change is needed.
"Knowing that these are life or death issues where over 100 people were killed as a consequence of failure, you would want to be really confident before you proceed with those reforms that you've got the detail right."
Ipenz said on Tuesday that, after taking legal advice, it is no longer investigating Dr Reay. He resigned his membership in February this year and the institute no longer has the authority to investigate his professional work.
Chief executive Andrew Cleland said the institution has very limited powers to investigate, even if Dr Reay was still a member of the voluntary body.
Dr Cleland said the complainants, including family members of those killed, have been informed of the decision and told Checkpoint he knows they will be upset.
"The families are bound to be disappointed. We did our very best to use the powers that we had, but those powers are very limited and ceased to exist once Dr Reay resigned."
But the lawyer for some families, Nigel Hampton, QC, believes that sends the message that professional engineers can avoid their obligations.
Mr Hampton said Ipenz obviously has a constitution that has been drawn far too narrowly and the decision is disappointing, but not a surprise.
One of the bereaved said it is unethical that the investigation has been dropped. Maan Alkaisi, who lost his wife Maysoon Abbas, said Ipenz should never have accepted the resignation.
Police are investigating Dr Reay's professional practice to see if criminal charges can be brought against him.
Alan Reay released a statement on Tuesday, saying his resignation had nothing to do with bringing an end to the disciplinary processes against him.
He said he expected to see them through to a conclusion and did not act out of fear of what might happen.
Dr Reay said by the time he resigned, he had come to have a complete lack of faith and trust in Ipenz because it failed to support its members in Christchurch after the Canterbury earthquakes.