Speaking on behalf of St Mary's, Archbishop of Wellington John Dew said before a priest was asked to join a parish, they went through a number of checks.
"When a priest of another country, diocese or religious order intends to work or visit in another diocese, before that can be confirmed, the priest's bishop or superior of the religious order must write to the bishop of the receiving diocese, to declare that to the best of his knowledge there are no circumstances, or complaints that he has, or is likely to, offend against any of the professional standards."
He said if the bishop of the receiving diocese did not receive a letter from the priest's bishop or superior, he would not be accepted to work at, or visit, the diocese.
"If accepted into the diocese they are then subject to all the relevant local requirements both of the law and church."
In New Zealand, additional steps were taken to ensure there were no no former complaints of sexual abuse, alcohol or substance abuse, Archbishop Dew said.
He said there was ongoing education of both lay people and clergy about appropriate boundaries, safe practices in ministry and awareness of signs of abuse or inappropriate behaviour.
St Mary's would continue to offer support to its parish following Kay's arrest, Archbishop Dew said.
"The court process is ongoing as the judge determines the appropriate sentence, as such we cannot discuss the case while it continues through the courts," he said.
"Our thoughts and prayers are with all involved and we continue to provide support to the Blenheim parish community."
Monsignor Gerard Burns, a visiting priest, had arrived over the weekend, and was offering support and reassurance to the St Mary's parish, a spokeswoman for the New Zealand Catholic Bishops said.
Kay was remanded on bail, and is due to reappear in court on October 20.
