Australian airline Qantas on Saturday announced to cancel 400 domestic flights due to on-going engineer strike.

Workers from the airline's engineering, long-haul pilots and ground crew unions have held strikes across Australia's airports, using public address systems to criticize Qantas and banned overtime as they seek higher pay and job security clauses in contracts.

According to Qantas spokeswoman Olivia Wirth, the fallout of ongoing disputes with pilots, unions and engineers is likely to cause disruptions throughout the Christmas period and beyond.

Wirth said the on-going strike forced the airline to ground four Boeing 737s and one Boeing 767 " for a month from Monday" at airports in Sydney, Melbourne, Brisbane and Adelaide, and will affect more than 60,000 passengers.

"We're asking the union leaders to stop taking this action against our business. The damage has already been done, they need to come back to the negotiating table," she said in a statement on Saturday.

While a planned four-hour strike in Adelaide and one-hour stoppages in Melbourne, Sydney, Brisbane and Adelaide have been postponed for two weeks, Wirth said this "will not help get these five grounded aircraft back up in the air."

However, the Australian Licenced Aircraft Engineers Association (ALAEA) has denied the cancellations are because of strike action, saying the aircraft are being grounded because of a lack of spare parts.

Prime Minister Julia Gillard earlier warned that the federal government can intervene in the dispute if the national economy becomes affected.

Opposition foreign affairs spokeswoman Julie Bishop said the ongoing dispute is damaging for the airline, and could also hurt Australia's reputation.

She urged all parties to negotiate a settlement of this matter as soon as possible, because the security of the Australian people and their ability to travel is at risk.