The NSW Law Enforcement Conduct Commission has outlined its concerns in a new report looking at NSW Police's system of "conduct management plans" for misbehaving police.

Officers with conduct issues - including problems as diverse as failure to investigate, discrimination, failure to keep people informed, or sexual harassment of colleagues - can be put on the plans if complaints are sustained.

A management plan means two more senior officers monitor them and give them guidance and feedback, usually for six months.

The aim is to hold the officer accountable for their actions and prevent similar conduct from happening again by modifying their behaviour.

But the LECC has questioned how effective the supervision is, pointing to rates of recidivism among the 168 officers put on a plan in 2017.

Seventy of the 168 - or 42 per cent - later had other conduct complaints against them upheld, the LECC's study found.

Some 22 of those committed similar misconduct to the type they had already been disciplined for.

The LECC was "particularly concerned" to find 11 were still on their management plan when they committed the further similar misconduct.

"This seems to indicate that the (plan's) strategies, which included close supervision and monitoring of the involved officers' operational activities, were not effective," the report states.

The report also found the length of time between the misconduct and the plan being implemented was often too long.

In one third of cases, the officer was put on the plan more than a year after the complaint was made.

In one case, an officer was placed on a three-month conduct management plan in 2017, nearly three years after an investigation had found he'd engaged in unprofessional and inappropriate behaviour.

That complaint had come after he'd already been found to have made unsolicited enquiries into the sex life of another officer in 2013.

The delay was due to the officer's appeal to an internal review panel, which took years to uphold the complaint.

The LECC made ten recommendations to improve the system.

Commenting on the LECC report, Greens MP David Shoebridge said the police force had "proven itself incapable of holding officers to account for misconduct".

"Even where police are found to have engaged in significant misconduct and been ordered to undertake Conduct Management Plans, it does little to reign in poor behaviour.

"NSW police have extraordinary powers and hopelessly inadequate accountability mechanisms which is a policy mix that does long term damage to police and society."

Australian Associated Press