The owners of Budapest Airport have decided to enter into a due diligence process, potentially taking the first step towards the sale of the asset, which Hungarian Prime Minister Viktor Orban's government has been looking to acquire for months.

"The Hungarian government has accepted our terms and conditions for starting formal negotiations," AviAlliance said in a statement on Monday.

"While this is potentially the first step towards the sale of the airport, we want to emphasise that the outcome of such a process is not predetermined."