(Adds details and background on deal and timeline) Oct 28...

(Adds details and background on deal and timeline)

Oct 28 (Reuters) - Australia's Qantas Airways Ltd (QAN) on Friday "expressed disappointment" at the country's competition regulator delaying its decision on the carrier's $394 million buy of Alliance Aviation Services (AQZ) .

The Australian Competition & Consumer Commission (ACCC) has delayed the provisional date to announce its final verdict on the deal three times so far, with the decision now expected on March 20, 2023. It began an informal merger review on May 18.

In May, Qantas said it was buying the remaining 80% stake in charter flights operator Alliance Aviation Services for A$610.8 million ($394.03 million).

The regulator, on its website, said the date was pushed back to give the parties more time to submit information. It was not immedietely clear what information had been sought.

The ACCC did not immedietely respond to a Reuters request for clarification.

The ACCC has previously said its preliminary view was that the deal was likely to hamper competition for air transport services to and from some remote parts of Australia for corporate customers.

Alliance Aviation's charter alliance agreement with Virgin Australia also hangs in the balance, with the ACCC proposing to deny approval for the firms to extend their agreement. If Qantas succeeds in buying Alliance Aviation, the charter alliance deal extension is even less likely to go through.

Alliance Aviation's shares last traded at A$3.23, a 32% discount to Qantas' offer price of A$4.75. ($1 = 1.5501 Australian dollars)