Dew had faced accusations of serious criminal sexual misconduct that allegedly occurred at St Joseph's Orphanage in Upper Hutt while serving as an assistant priest there.
The alleged abuse is claimed to have taken place in November 1977, at a time when the accuser was placed in an orphanage operated by the Sisters of Mercy, remaining there for 10 days.
Cardinal Dew said he first heard of the allegation May 6 last year, a day after he retired as Archbishop of Wellington.
"I am writing to you regarding recent media coverage of an allegation against Cardinal John Dew about events alleged to have taken place in the 1970s.
The New Zealand Police investigated the allegation. They have stated that they have concluded their investigation and no charges will be laid," Archbishop Paul Martin of Wellington wrote March 7 in a letter to the people of all the country's parishes, schools and Catholic agencies.
Church inquiries to proceed
Cardinal Dew stepped down from his role as Archbishop of Wellington in May last year upon reaching the age of 75, which is the standard retirement age for Catholic bishops.
Following the Church's protocols, Cardinal Dew withdrew from all public church activities once the allegation was made known to the Church. Throughout this process, Cardinal John has maintained his innocence, Archbishop Martin said.
"Inquiries by the Church are not run concurrently to those being undertaken by the Police. Now that the police investigation has concluded, Cardinal John continues to stand aside while Church inquiries proceed," Archbishop Martin said.
Cardinal Dew had tried various legal avenues to block the Newshub media company from publishing allegations of sexual abuse against him.
He attempted to secure an injunction to halt the story, initially approaching the High Court and then the Supreme Court without success.
Dew in a statement expressed gratitude towards numerous witnesses who provided affidavits confirming the alleged incident could not and did not occur.
In a statement, Dew mentioned he is unfamiliar with the accusers and has never encountered them.
Dew represented the Catholic Church during the Royal Commission investigating abuse in State Care and Faith-based Institutions, acknowledging that "we caused you pain, hurt and trauma and this continues to impact you". "Any kind of abuse is unacceptable and indefensible. We are deeply sorry," the cardinal had said.
He pointed out that he would not have been able to testify and issue a public apology on behalf of the New Zealand Catholic Church if the allegations against him were true.
"The word 'integrity' has always meant a great deal to me"
"The word 'integrity' has always meant a great deal to me, and those words have guided my life" Cardinal Dew told CathNews New Zealand.
On being interviewed by the policed him about the allegation, Dew said: "I stated immediately, and state again now, that there have never been any instances of improper or abusive behavior in my 48 years of priesthood."
Dew is also the focus of a separate investigation by the Church. This investigation follows the "Vos estis lux mundi" process, a Vatican-initiated procedure that assigns a critical role to the Metropolitan Archbishop in managing a Church investigation when there are sexual abuse allegations against a bishop, priest, or deacon.
After the investigation is completed, its findings are forwarded to the Holy See.
Archbishop Martin, as the current Metropolitan Archbishop of New Zealand, has taken over the responsibility of overseeing the "Vos estis" investigation into his predecessor.
Dew has been suspended from his ministry duties during the ongoing Church investigation.
Dew was ordained to the priesthood in 1976. He served as an assistant priest at St Joseph's Parish in Upper Hutt from 1976 to 1979, the period during which the alleged abuse took place.
In 1995, he was ordained as Auxiliary Bishop of Wellington Archdiocese.
John Paul II appointed him as coadjutor Archbishop of Wellington in 2004, and he headed the archdiocese a year later.
Pope Francis made him a cardinal in 2015. Dew also held the position of president of the New Zealand Catholic Bishop's Conference.