Papua New Guinea's Inter-Government Relations Minister Sir Peter Barter says the Fiji men wanted for questioning in Bougainville appear to have been recruited by a fugitive, Noah Musingku.
Sir Peter has told the newspaper, The National, that it is incorrect to refer to the group as mercenaries.
He says the men appear to have been recruited by Mr Musingku to train members of his security.
They are reported to have entered PNG legally but the Fiji high commission in Port Moresby says it wants the men to return to Fiji.
Mr Musingku is wanted in connection with his fast money schemes.
He was in Solomon Islands two years ago negotiating a massive loan to the government which ignored PNG requests for his extradition.
At the time, Mr Musingku claimed he was a Solomon Islander.