More than 6,100 passengers will be affected on Tuesday by the Transport Workers Union's strike with Qantas forced to cancel 28 flights and delay a further 27 flights by up to 35 minutes.

Qantas said it has been able to significantly reduce the full impact of the strike by using larger wide-body aircraft and deploying Australian-based Qantas management to act in operational roles.

"There could be further delays over the next two days as a result of the flow on effect from the strikes and the 48 hour ban on working higher duties," the Qantas statement said.

It said customers wishing to get up to date flight details should visit qantas.com. Customers on cancelled flights or flights delayed by more than 15 minutes will be contacted.

Qantas Group Executive Olivia Wirth said the airline was focussed first and foremost on getting passengers to the destinations as quickly as possible.

“We apologise to our passengers who will be caught up in this strike action from the Transport Workers Union. The TWU is intent on causing disruptions to Qantas passengers and we are doing everything we possibly can to reduce the delays and cancellations,” Wirth said.

Wirth said that the TWU were taking strike action as part of an ongoing pay dispute.

“The TWU are asking for 15 per cent pay increase over the next three years which is just not sustainable in the current economic climate and when these employees are already the highest paid in the Australian aviation industry,” she said.

“The union is also trying to place restrictions on Qantas which would remove our flexibility to scale up or scale down our workforce in line with busy and quiet periods," the official said.

She said the union is willing to allow its members to be paid 12 percent less at Virgin and to enable them to have a lower pay scale for new starters but they are demanding that Qantas does not have the same flexibility.

“We have been in negotiations with the TWU since May and are willing to offer reasonable pay increases. We encourage the TWU to remain at the negotiating table instead of going on strike.”

The TWU claim includes a 5 per cent pay increases for every year of the agreement, an additional one per cent compulsory employer superannuation contribution every year of the agreement and requirement for site rates.

Wirth said Qantas was very concerned that three unions were working together to attack Qantas in a coordinated campaign.

“While Qantas is focused on building a better airline for our customers, employees and shareholders, three separate unions are taking coordinated industrial action and holding our passengers to ransom," she said.

“Strike action by the Australian Licenced Aircraft Engineers Association in Sydney tomorrow (Tuesday) will see more than 800 passengers affected by six flight delays. Since the engineers’ union started taking action in late August more than 10,000 passengers have been affected,” she added.