Heartbroken families of the CTV victims will have to wait nearly two weeks to ask police why nobody will be held responsible for their deaths.

Police said they did not have enough evidence to lay charges after a four-year, million dollar investigation into the CTV collapse, killing 115 people.

Police initially looked to charge Dr Alan Reay and David Harding with negligent manslaughter, but dropped the case on legal advice.

Detective Superintendent Peter Read said they also considered charging the pair with criminal nuisance.

"There's a higher standard of proof because we have to prove knowledge around recklessness, so it would've been a harder case to actually establish than negligent manslaughter".

A Royal Commission of Inquiry found the building should not have pancaked the way it did, and there were design flaws from the get-go.

Read said they want to talk through the decision with the families.

"We also wanted to make sure the legal experts were there when we met with the families so that there could be a discussion. The earliest opportunity we could do that is December 14".