Tuffey, dumped from the national squad in the current series against Australia for lack of form, admitted a charge of serious misconduct brought by the cricket body.
An independent inquiry conducted by a prominent lawyer found Tuffey last November engaged in conduct with "a sexual element" with the woman, which was recorded on a digital camera.
Tuffey, 26, and the woman were not having sex and had no prior knowledge of the filming, lawyer Hugh Rennie said.
However, Tuffey did nothing initially to recover the recording or stop it being shown.
"He made a serious misjudgement in becoming involved, and a further error in not taking any action to have the recording destroyed," Rennie said in his report.
"Mr Tuffey accepts that the existence of this recording takes his conduct outside his private rights in respect of his off field conduct."
Tuffey, as an international sportsman, had a special status in society and obligations arising from his involvement in commercial sport, Rennie said, adding that his contract required him not to "act contrary to the interests" of NZ Cricket.
He had expressed regret for his actions, which could have resulted in the cancellation of his contract, Rennie said.
Tuffey has been one of New Zealand's front line pace bowlers since he was first selected in 2000. He has 66 Test wickets and 90 one-day international wickets.
External link: Witness reveals Tuffey sex tape details
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