The head of the NSW Sex Crimes Squad has conceded alleged child sexual abuse in the Hunter Valley's Catholic Church was not investigated with much urgency.

On day five of the special commission of inquiry's public hearings at Newcastle Supreme Court, the commander of the NSW Police Sex Crimes Squad Detective Superintendent John Kerlatec was giving evidence.

The probe is examining claims by abuse whistleblower Detective Chief Inspector Peter Fox he was directed by superiors to stop investigating the allegations of abuse by two priests in the Catholic Diocese of Maitland-Newcastle.

Detective Fox's barrister, Mark Cohen, suggested police emails showed there was not much urgency among Strike Force Lantle investigators to examine the claims.

Detective Kerlatec agreed and conceded that while an investigating officer appeared keen to proceed quickly, he was being shut down by his superior, Detective Inspector Dave Waddell.

But Detective Kerlatec rejected claims that Strike Force Lantle was designed to fail.

Mr Cohen also suggested there was a "blockage" when it came to material sent to police by local Fairfax newspaper journalist Joanne McCarthy.

Detective Fox return to the witness box for a fifth day, after Detective Kerlatec.

The inquiry continues.