HIGH AND DRY: A helium-inflated shark like one reported by a jet pilot on a flightpath to Christchurch Airport is tested by Press reporters Michael Wright, left, Keith Lynch, right, and Marc Greenhill, obscured.

Inflatable sharks that were a hit at Christmas are heading for the exits around the country and flying off into the wild blue yonder.

Reports of escaping sharks have come in from homes as far apart as Auckland and Riverton in Southland.

The issue first drew attention when the pilot of a passenger jet on his descent to Christchurch International Airport on Boxing Day radioed ground control with a sighting of a shark flying at several thousand feet.

The fish out of water was identified as a remote-controlled, helium-filled shark that has topped must-have present lists this Christmas.

Claims of possible ownership of the sighted high flying fish have come from bereft households in Hamilton, Feilding, and two from Christchurch.

MetService said working out where an escaped shark might have travelled to would be a difficult task. Factors would include the amount of helium in the fish, affecting its height, along with wind speed and direction.

The 1.44-metre-long Air Swimmer toy has a radio receiver attached to its underside and can be operated by remote control over a range of 15m.

Designer-developer William Mark Corporation warns that the shark is for "strictly indoor use only".

A spokeswoman for air traffic control company Airways, Monica Davis, said a pilot had reported the shark and its location about nine kilometres from the airport at 2pm on December 26.

"We advised subsequent traffic of its location, but no-one else reported seeing it."

It was not yet known whether the sighting would be formally logged as an air-safety incident, she said.

The shark's altitude and how close it came to the plane were unclear, Davis said.

The Civil Aviation Authority had not received a report of any shark encounters, but because the Christchurch incident was only a sighting, there is a 30-day reporting period.

Accidents must be reported within 24 hours.

New Zealand Air Line Pilots' Association president Glen Kenny said a helium-filled shark would not pose a serious risk if it was sucked into an aircraft engine.

"The engine probably wouldn't stop, but it would do a bit of damage," he said.

"Helium is an inert gas, so there's no issue in that regard. The biggest hazard would be startling the pilot."

Wayward party balloons had been an air-safety issue overseas, especially in the United States, Kenny said.

He had heard about the Christchurch shark incident and had some experience with the toy, having bought his daughter the 91-centimetre clownfish version for Christmas.

He hoped common sense would prevail as people tried out their helium-filled toy.

"It says it's an indoor toy on the box. If you take them outside and the wind gets them, they can be goneburger, so you've got to be a bit careful," he said.

The Air Swimmer was created by 19-year-old Stanford University student Blake English and has proved to be one of the most popular toys worldwide since its release in July.

They retail in New Zealand for $99 (helium not included) and should not be operated outside, near water or by children aged under three.

The Top Christmas Toys website rates the Air Swimmer as one of the best of 2011, describing it as "great fun for indoor family get-togethers and children's parties".

It recommends users turn off ceiling fans while operating the device "for both safety and control".