The complaint against Tialavea Tionisio Hunt and his spouse was made by a sacked prison officer to the prime minister, who asked the ombudsman to look into the claim.
The former officer alleged the associate minister's wife, who holds a senior position in the prison administration, breached the normal process for employing new staff by appointing members of her own family.
He has also accused her of unlawfully sacking him after a tribunal said allegations of poor performance and of him having an affair with a colleague were unproven.
