There are calls for a full judicial inquiry into possibly corrupt and illegal conduct in the New South Wales Police Force dating back more than a decade.

Premier Barry O'Farrell has ordered the State's Ombudsman to carry out an inquiry into a series of allegations about police phone tapping and bugging other police.

But some say that does not go far enough.

The saga threatens to blow into a full-scale scandal and the timing may have more than a little do with the order of succession in the top ranks of Australia's largest law enforcement agency.

In 1999, a top secret operation by internal affairs to hunt down crooked cops became a runaway investigation that lasted more than two-and-a-half years.

In recent months, details of what went wrong have been finding their way to Sydney Sun Herald journalist Neil Mercer.

"The allegation is they falsified information to obtain search warrants, to obtain telephone taps and to obtain listening devices and that's come out in recent weeks and that is where we are at at the moment," Mercer said.

He says the alleged motivation is unclear.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 4 minutes 18 seconds 4 m 18 s Call for police misconduct probe Download 2 MB

"It's a little hard to answer although we do know this, one of the key undercover operatives in this operation was working for special crime and internal affairs," Mercer said.

"He is on the record now - well we've found this out in the last few weeks - he says he was being used, in part, to settle old scores.

"In other words revenge against other New South Wales Police was in his view one of the motivations for this."

'Wild tangents'

Up to 200 police officers may have been spied on with listening devices and telephone intercepts.

Among them is the man who aspires to become the next commissioner, Deputy Commissioner Nick Kaldos.

One of the special crime and internal affairs officers targeting Deputy Commissioner Kaldos was Catherine Burn, who is now also a Deputy Commissioner.

"So you have a Deputy Commissioner of the New South Wales Police Force, Nick Kaldos, who was a target 10 years ago and one of the people looking at him is also now a Deputy Commissioner," Mercer said.

"This operation went off the rails, they had some legitimate targets and then as one of the sources that we've drawn on said, it went off in 'wild tangents'.

"They were targeting people on third, forth-hand hearsay. They were targeting people as get squares according to one of the key undercover operatives involved in this.

"It smells, it stinks."

Transparent inquiry call

The stench has become too much to ignore in Macquarie Street, prompting Mr O'Farrell on Saturday to order the State's Ombudsman, Bruce Barbor, to get to the bottom of the scandal.

Greens MP David Shoebridge has been campaigning on the issue and says much more should be done.

"Well the government's failed to set up a transparent inquiry," Mr Shoebridge said.

"The Ombudsman will not be holding public hearings and will not have the full range of powers that a royal commission or a full judicial inquiry would have.

"The Government's made this decision on Saturday clearly with full knowledge that this Thursday, in budget estimates, senior police were going to be facing direct questions about there role in the police wire-tapping scandal and to avoid, seemingly to avoid police answering those questions in budget estimates."

ABC journalist Quentin Dempster has been following the many sagas of police and institutional corruption - he suspects this back to the future scandal has real implications for the future.

"I think Catherine Burn would have the greatest to lose if there's any adverse findings, at the moment there is no adverse findings against Catherine Burn," Dempster said.

"Kaldos joins a number of those 54 officers who are aggrieved and obviously deeply hurt by the fact that this hasn't been cleaned up."