Pornography found on the work computer of former deputy commissioner Jevon McSkimming is being investigated as alleged objectionable material, RNZ understands.

McSkimming resigned as the country's second most powerful cop on Monday amid a four-month investigation by the Independent Police Conduct Authority and police.

RNZ understands his resignation came after he was confronted with allegations that pornography, being investigated as alleged objectionable material, was found on his work computer.

McSkimming declined to comment on the allegations through his lawyer.