Qantas has assured disrupted passengers they will have no problem accessing free flights being offered as a goodwill gesture while pilots said it will take more than that for the public to forgive airline management.

The airline today said that the free return economy flight being offered to more than 70,000 passengers affected by the grounding was completely separate to its compensation packages or any other payments.

But passengers deprived of their business class flights will have to fly economy if they wish to take up the Qantas free offer, which the airline estimates will cost it about AU$20 million.

It takes the cost of the grounding to above AU$50 million.

The pilots' union today dismissed offering free tickets as a waste of airline money, pointing to a survey which they claimed showed people blamed the Qantas management more than unions for damaging the airline's reputation.

An eMc Essential Report survey of 1906 people found 59 percent said the grounding had most damaged the airline's reputation, compared to 32 percent blaming industrial action by Qantas unions.

The survey found 53 percent of respondents disapproved of the grounding, while 35 pentcent approved.

Asked who was to blame, 41 percent nominated Qantas management, 20 percent said the workers with 31 percent saying both were equally to blame.

"People know that it was completely unnecessary of Mr Joyce to leave 68,000 people stranded around the globe," Australian International Pilots Association vice president Captain Richard Woodward said.

Qantas spokesperson Emma Kearns said free return tickets, available to anyone who purchased a Qantas ticket but could not fly on the grounded airline, will not be rationed or taken out of the allocation reserved for Frequent Flyer travelers.

"We will be carefully monitoring availability and request for tickets, it is subject to availability but we're not anticipating a rush on any particular route," she said.

Frequent Flyer points can be redeemed on the free tickets according to the passenger's class of membership, but the offer is not transferable.

Those passengers who swapped Qantas tickets for Virgin Australia tickets to beat the grounding, with Qantas paying any extra fare, will still be eligible for the free flight she said.

But final details are expected to be sent to Qantas passengers as early as tomorrow on how to access the tickets.

Anyone who bought a Qantas ticket in Australia, either a domestic or international ticket, will be eligible for a free return flight.

Flights will become available from the end of this month and journeys can be made until December 2013, with passengers booking a minimum of 14 days and a maximum of 90 days in advance.