"In addition, it is plain from what we have seen that there has been a major change in Mr Tai."
Tai is to undertake a rehabilitation programme and is on the waiting list for a drug treatment programme, which could start next month in prison.
The board said Mr Vercoe's family was concerned over Tai's involvement with the alcohol and drug situation in Opotiki and the need to deal with that.
The board agreed Tai needed to complete the programme so he would not give in to the temptation of drugs and alcohol once released. The board said he remained a risk to the community until then.
Tai can be considered for parole again at the end of this year.
New Zealand Parole Board communications manager Sonja de Friez said the main priority was the safety of the community and the board had considered the likelihood of further offending and the possible nature and seriousness of that prospect.
"The assessment of risk is a very strenuous and scientific process," she said. "Every board member takesthe views of each victim very seriously."
Mr Vercoe's family could not be contacted for comment.