The Jehovah's Witness Church in Australia hid allegations of child sexual abuse involving more than 1000 of its members over 60 years, a royal commission has heard.

The organisation, which has almost 70,000 active members in Australia, failed to report serious abuse claims to police in favour of internal investigations overseen by church elders.

The opening day of the hearing into the Jehovah's Witnesses at the Royal Commission into Institutional Responses to Child Sexual Abuse heard that detailed notes about sexual abuse allegations were destroyed in case they fell into the "wrong hands".

Church elder Max Horley​ told the commission the organisation did not report abuse to police but encouraged victims to do so.

When asked by commission chairman Justice Peter McClellan​ how victims were encouraged to go to the police, Mr Horley replied: "My understanding is a little unclear because I've never had to do it."