Police Commissioner Karl O'Callaghan has admitted he is almost powerless to dismiss officers under current disciplinary procedures.

After the resignation of the second police officer involved in the wrongful murder conviction of Andrew Mallard, Mr O'Callaghan admitted he had concerns with the Section 8 "loss of confidence" process.

Former assistant commissioner Mal Shervill was facing disciplinary action for his role in the murder investigation of Pamela Lawrence but quit on Tuesday before the inquiry could be completed. He had been stood down on full pay since 2005.

Mr Shervill maintains he did nothing wrong during the investigation.

Mr O'Callaghan said yesterday that his concerns did not directly relate to Mr Shervill's case.

"Even if I determine that an officer should be sacked, as the legislation is currently constructed that officer still has the option of resigning after they've been told they'll be sacked," he said. "In other words, it is almost impossible for the Commissioner of Police to sack a police officer."

Mr O'Callaghan said he was seeking legal advice before discussing it with Police Minister Rob Johnson.

Mr Johnson said he would consider any submission but did not want to comment until he had spoken in detail to Mr O'Callaghan. It does not make a financial difference if a police officer resigns or is sacked but it can affect their future career prospects.