Convicted child murderer Hayden Wallace is claiming he was moved between jobs inside Rimutaka prison as punishment over allegations he made against an officer.
However, the inmate said he was being punished because he saw the woman kissing and carrying on with a manager inside Rimutaka prison.
His lawyer is demanding a fully independent inquiry.
Wallace is serving a minimum 15 years for killing Whanganui toddler Jhia Te Tua in a driveby shooting in 2007.
He was moved out of a cleaning job and into another job in February, and was moved between units, and then lost further privileges in May.
"There is evidence ... that the prisoner has failed to recognise the limitations of prisoner/staff relationships which are essential for the physical and emotional safety of all," a prison inspector's report, released under the Privacy Act said in September.
Wallace "pressured her and wanted more from her than she was able to provide", she told the prison's deputy director.
In an 11-page signed statement to the prison's integrity support team in June, Wallace said the officer told him about her relationship problems, they exchanged about 30 letters, and "she indicated that she had feelings for me".
He "felt threatened and manipulated ... I felt like I had to do what I was asked [or] I might lose my job".
Around Christmas time 2016, Wallace claimed he came across the woman and a manager kissing and being intimate, and that she saw him, which led to her making serious allegations against him.
"She wanted to get in first," Wallace's lawyer, Michael Bott, said.
"Just because my client's done a bad thing in the past, that doesn't mean the department's entitled to treat him like rubbish in the future."
Corrections said in a statement to RNZ yesterday that the staff that were the subjects of the allegation were spoken to and both denied that the incident had occurred.
However, it said the investigators did not interview either the prison officer or her manager, because she was on leave and because the manager took no part in terminating Wallace's cleaning job.
These gaps showed the investigation was inadequate, Mr Bott said.
The manager has since left Rimutaka, taking a senior job at another prison, Corrections said.
The female officer was sanctioned for an inappropriate relationship with a prisoner because she brought in craft materials for him. Wallace said the officer brought him paints and got him to do carvings for her.
After Wallace lost the cleaning job, a prison guard filed a note questioning why, saying Wallace was "doing an amazing job" and adding that he "is getting the run-around".
Large parts of the investigation report, released to Mr Bott were blanked out.
Prison inspectors upheld 3 percent of complaints in the year to mid-2017, or 23 out of 845 complaints.