Virgin Australia says its flights are back on schedule after thousands of passengers were stranded due to a glitch in the airline's check-in service.

Virgin was one of several airlines affected by problems with the Sabre booking and check-in system on Tuesday, forcing it to cancel 30 flights across its domestic and international network.

The airline on Wednesday said its flight schedule was back to normal, but that passengers could still expect delays of up to an hour on Wednesday morning.

"We are back on schedule ... There may be some minor delays, but they should be cleared by midday," a Virgin spokeswoman told AAP.

She said three flights had been cancelled on Wednesday "as a result of the outage yesterday".

Those flights were on routes between Sydney and Melbourne, and Sydney and Brisbane.

She reiterated Virgin's offer of a refund to passengers impacted by cancellations.

"Our special compensation policy that we released yesterday also applies to today," the spokeswoman said.

People who miss flights will be provided with a full credit for the cost of the flight and customers will be able to change their flight to the same destination to another service until August 13 for free.

Customers stranded overseas may be eligible for hotel accommodation.

 

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