AirAsia, Asia's biggest budget airline, will kick off the sale of a majority stake in its plane-leasing unit this month, a deal that could value the business at about $1 billion, people familiar with the matter told Reuters.

The Malaysia-based carrier, headed by tycoon Tony Fernandes, has hired three investment banks to run the sale of the Asia Aviation Capital stake, the people said. They declined to be identified as the discussions were confidential.

The deal would help AirAsia boost its finances and slash debt after it faced criticism last year for its accounting practices. At an overall valuation of $1 billion, the sale would be significant for a carrier with a market capitalization of $2 billion.

AirAsia declined to comment.

The airline plans to tap potential suitors including the leasing units of China's HNA Group, China Merchants Bank, and the aviation leasing company backed by Hong Kong billionaire Li Ka-Shing for the sale, the people familiar with the matter said. China Merchants Bank, HNA Group, and Li's CK group did not respond to Reuters' requests for comments.

AirAsia was also open to selling the unit completely, they said, and its final valuation could change depending on how talks with potential buyers proceed. The people said the carrier is considering paying down debt or paying a special dividend from the proceeds.

They said AirAsia has hired Credit Suisse, BNP Paribas, and RHB Bank to handle the sale, and expects to complete it by early next year.

BNP Paribas and RHB Bank declined to comment, while Credit Suisse did not respond to Reuters requests for comments.