Police have dismissed conflict of interest concerns about a north Queensland detective's involvement in investigating the death of Shandee Blackburn, despite the senior officer being the aunt of a former "person of interest" to the murder.

Key points: The Crime and Corruption Commission referred a complaint about the involvement of two officers to the QPS

The Crime and Corruption Commission referred a complaint about the involvement of two officers to the QPS It found "no misconduct or breach of discipline", despite one officer's relation to a former "person of interest"

It found "no misconduct or breach of discipline", despite one officer's relation to a former "person of interest" The CCC suggested a further complaint be a matter for an inquest, but the coroner says any police investigation was outside the scope

The Crime and Corruption Commission (CCC) this week confirmed it had previously received a complaint, which the ABC understands related to two officers linked to the investigation into Ms Blackburn's 2013 stabbing murder in Mackay.

But the officers — Detective Senior Sergeant Samantha Bliss and arresting officer Lisa Elkins — were cleared, after the CCC referred the matter to the Queensland Police Service (QPS).

In a statement, a QPS spokesman said "no misconduct or breach of discipline was identified", after assessing the complaint.

The ABC has been told a further complaint was made to the CCC, which the watchdog suggested could be a matter for a July inquest that is set to examine the circumstances of her death.

But at a pre-inquest hearing in Mackay this week, Coroner David O'Connell said concerns over the adequacy of the police investigation were outside the scope, which will include exploring whether extra CCTV cameras or street lighting should be installed in high risk areas.

Ms Blackburn was stabbed more than 20 times, just metres from her house, as she walked home from work in February 2013.

Ms Blackburn's former boyfriend, John Peros, was later charged with her murder, but was acquitted by a jury following a 12-day trial in 2017.

Another man initially considered a "person of interest" in the case was William Daniel — the nephew of Det Snr Sgt Bliss — and during this week's pre-inquest hearing, Mr Peros's barrister Craig Eberhardt claimed there had been a conflict of interest in relation to the investigation.

Shandee Blackburn's boyfriend was acquitted of her murder in 2017. ( Facebook, supplied by family )

He argued there was an "overwhelming prima facie case against" Mr Daniel and said samples taken from Ms Blackburn's clothes were 13 times more likely to have come from him, than a member of the public.

The court heard Mr Daniel left Queensland because of the rumours he was responsible for the murder, and phoned his aunt when police contacted him.

She then travelled to Broome to take a statement from Mr Daniel's ex-partner, Mr Eberhardt said.

"In addition to that, it turns out, Samantha Bliss is a close personal friend of the arresting officer, Detective Sergeant Lisa Elkins," he said.

"For reasons that are entirely unclear and unanswered, Lisa Elkins decided to arrest and charge John Peros."

Mr Daniel has denied any involvement in Ms Blackburn's death.