DUBAI, Jan 5 (Reuters) - Abu Dhabi state fund Mubadala Investment Co and UAE-based conglomerate Alpha Dhabi plan to deploy up to 9 billion dirhams ($2.5 billion) in credit markets through a new joint venture, the companies said on Thursday.

The two companies plan to leverage on Mubadala's relationship with U.S. asset manager Apollo "to access high-quality private credit investment opportunities", they said in a joint statement with Apollo.

Mubadala will own 80% of the venture, which will be based in Abu Dhabi Global Market, the emirate's financial freezone. The remaining 20% will be held by Alpha Dhabi, the statement said. ($1 = 3.6726 UAE dirham) (Reporting by Hadeel Al Sayegh; editing by Uttaresh.V)