Staff at Queenstown Airport were picketing in the snow this morning with no end in sight to their pay dispute with Mount Cook Airlines.

The 49 baggage handlers and ticketing staff walked off the job on Friday in their quest for a 5 per cent pay rise.

Engineering, Printing and Manufacturing Union spokeswoman Libby Carr said the strike had continued all weekend and was under way again today.

"Our picket line is up and running in the snow. The tent's just been put up," she said.

Ms Carr said the strike would continue indefinitely. "There's no movement from the company at this stage but we didn't expect any."

Mount Cook management and staff have been called from other areas to replace striking staff.

The company says there have been no delays or safety issues, but Ms Carr said the union believed some of the staff were not certified for the jobs they were doing.

"We have expressed our safety concerns in terms of some of the thing we have observed when we have been in there to monitor."

She said an extra trolley load of luggage had been added on to a plane.

"People might say 'what's the significance of an extra load?' but a plane needs to be weighted properly for take-off and landing.

"If the fill-in staff are not picking up an entire trolley full of luggage, what else are they missing?"

Mount Cook Airlines general manager Peter O'Regan yesterday said all flights had operated on time.

"There's been no impact at all."

Air New Zealand communications manager David Jamieson said suggestions from EPMU that a Boeing 737 had been overloaded were incorrect.

People who loaded aircraft required special licensing -- including the fill-in staff -- and a computer programme calculated the weight and balance of the baggage and freight, he said.

"I don't know how the union manages to suggest that a whole extra trolley load of luggage could have gone into the back of a 737 -- it just cannot happen.

"Even the managers who have been drafted in to load the aircraft because of the industrial action must be qualified.

"They have to have a certificate, it's a CAA (Civil Aviation Authority) requirement."

Mr Jamieson said the company was still waiting to hear back from EPMU on the pay talks.

"We're still in negotiations with the union."