The $7.5 billion sale of most of Nokia's phone business to Microsoft was expected to close in the first quarter.
Reuters said that Microsoft has also expects the deal to close in April.
The deal has been rubber stamped by the authorities in the US and EU but apparently some antitrust authorities in Asia are still conducting their reviews, it said in a statement.
Brad Smith, Microsoft's general counsel, said on the company's bog that Vole was nearing the final stages of our global regulatory approval process.
"Currently we are awaiting approval confirmation in the final markets."
The company last week was given a new $414 million tax claim by Indian authorities, following a recent Supreme Court decision to order Nokia to give a $571 million guarantee before transferring its Chennai factory to Microsoft.
Nokia said its tax disputes in India would not have an impact on the deal schedule.
Observers are not too stressed at the delays. It took Vole five months to complete its purchase of online chat company Skype in 2011.