Border alerts were flagged up within 24 hours of Mr Beckenridge allegedly abducting Mike Zhao-Beckenridge (11) on March 13 during the a lunch break from James Hargest College's junior school in Invercargill.
More than a week after they disappeared in Southland, Mr Beckenridge's car was found at the bottom of an 88m cliff near Curio Bay. Their bodies have not been found.
Police are now treating it as a missing persons case.
Mr Beckenridge's friends and neighbours say he would never hurt Mike, and believe he has faked their deaths and is hiding out in either New Zealand or abroad.
Interpol, the intergovernmental police organisation with branches in most countries around the world, has been enlisted to help in the hunt for the pair.
The Wellington National Central Bureau (NCB) Interpol office has been involved in the case and are being kept up to date with the investigation, acting Southland area commander Inspector Kelvin Lloyd confirmed to NZME. News Service today.
"Part of this involvement has been liaising with their counterparts in other offices in other countries," Mr Lloyd said.
He would not reveal which overseas offices or inquiries have been made, saying it forms part of the investigation.
Swedish-born Mr Beckenridge (64) is an experienced commercial helicopter pilot who up until September last year had been working as a full-time pilot for Pacific Helicopters PNG - an aviation firm based in Papua New Guinea Eastern Highlands province capital Goroka that flies for the oil, gas, mining, drilling and construction sectors.
Pacific Helicopters PNG chief executive Mal Smith told NZME. News Service that New Zealand police have been speaking with the company.
"We have given all of our information to [New Zealand] police. We knew he had problems with his wife, and problems getting access to his kid, but we didn't know it was to that extreme."
Mr Beckenridge, also variously known as John Robert Lundh, Knut Goran Roland Lundh, and John Bradford, was not a registered pilot with the New Zealand's Civil Aviation Authority, it confirmed.
Meanwhile, the civil aviation safety authorities of Australia and PNG have refused to release pilot licence information, citing privacy legislation.
