DUBAI- Saad Group and bank creditors of the Saudi Arabian conglomerate have both selected advisers in a bid to try to reach a deal that could help end the kingdom's largest and longest-running debt dispute, financial sources said on Thursday.

The appointments of London-based Orchard Corporate Strategy by Saad and EY by creditors, is the latest attempt to reach an agreement that will be complicated by an ongoing auction of the company's assets.

One of the sources said creditors were seeking to engage with the court overseeing an auction process to try to avoid a fire sale of assets and disorderly liquidation of the company in order to secure a better deal for creditors.

Proceeds from the auctions, which have included machinery, vehicles and now real estate, are intended to help repay creditors, which includes local and international banks, Saad staff and trade creditors.

An auction of real estate assets owned by Saad's owner, billionaire Maan al-Sanea, started on Dec. 2.

EY declined to comment. Orchard and Saad Group didn't respond to requests for comment.

Saad Group defaulted together with Ahmad Hamad al-Gosaibi and Brothers (AHAB) in 2009, in what was Saudi Arabia's biggest financial meltdown, leaving local and international banks with unpaid debt of about $22 billion.

The government in 2016 formed a three-judge Joint Directorate of Enforcement at the General Court in Al Khobar (JDEK) and the court has begun a liquidation process for Saad Group.

Sanea, once ranked among the world's 100 richest people by Forbes, was detained last year for unpaid debts dating back to 2009 when Saad defaulted.

(Editing by Elaine Hardcastle) ((Tom.Arnold@thomsonreuters.com; +97144536265; Reuters Messaging: tom.arnold.thomsonreuters.com@reuters.net))