Police Minister Stuart Nash holds him in high regard, telling Newshub: "I think you have to look at Mike Clement's record over the last 42 years and he's done an incredible job."

But Clement is being investigated by police watchdog the Independent Police Conduct Authority (IPCA) and the investigation is expected to wrap up shortly.

Newshub understands the investigation relates to a complaint that Clement interfered with the appointment of a senior police officer late last year.

It's alleged that after someone was appointed as Superintendent, the role was taken off them after Clement stepped in.

After a complaint was laid with Police and the IPCA, the person was reinstated.

Newshub asked the Police Minister if he's waiting for the IPCA to complete its investigation into Clement before an appointment is made to replace Bush.

"We're just going through a good process," Nash replied.

When asked about the allegations Clement interfered in an employment process, Nash said all he knows is that there's "something going on" but that he's "not over the details".

Another Deputy Police Commissioner, Wally Haumaha, was investigated by the IPCA last year. It found he belittled and intimidated two women. That report was released publicly but this one won't be, with the IPCA citing privacy.

Newshub asked Nash if he thinks the report should be released, and he replied: "I don't know."

Outgoing Commissioner Mike Bush leaves in April, and usually the replacement would have been announced by now.

"There's no hold-up - we're going through a process we need to make sure we get this right," Nash said. "This is one of the most important jobs in the state service."

But while preparing for an interview on Tuesday, Bush told Newshub: "It's normally done by now but they're just taking their time a little."

A major review into police culture and bullying released on Tuesday warned police they needed to reduce bias in appointment processes.

We don't know whether the IPCA will uphold the complaint against one of our most high ranking police officers - and we may never know.

If you have more information and would like to contact Tova O'Brien in confidence, email tovaobrien@mediaworks.co.nz.