One-time coal billionaire Nathan Tinkler has sold his Patinack Farm racehorse operation.

Patinack has been sold to a consortium of local and overseas buyers, including Middle East-based investors, but the sale price has not been disclosed.

Mr Tinkler put Patinack on the market more than a year ago, with the now-Singapore-based businessman saying he no longer had time to run the business.

Industry sources put the possible sale price at between $100 million and $200 million when Patinack was placed on the market in 2013.

In a statement on Wednesday, Mr Tinkler said his Tinkler Group was concentrating on resources projects.

"As I now reside overseas and my focus is on our core operations in resources and mining, I am pleased to secure new owners who will take this project forward," he said of Patinack.

"The sale will allow further capital to be used in the development of our existing operations."

The sale was negotiated by a United Arab Emirates-based investment company, Cibola Capital and is to be completed within weeks.

Cibola Capital chief executive Daniel Kenny said the consortium wanted to expand the Patinack business "by investing in breeding and racing across Australia and internationally".

The Patinack sale includes 600 horses and properties in NSW, Queensland and Victoria, including the major Sandy Hollow breeding facility in the NSW Hunter Valley.

Mr Tinkler has been back in the headlines recently after giving evidence at a corruption inquiry into political donations in NSW and reports he has bid for a Queensland coalmine.

The one-time coal baron's fortune has slumped and in 2013 he faced a liquidator's investigation into his assets after one of his companies, Mulsanne Resources, was wound up over a $28.4 million debt.