DUESSELDORF, Germany (Reuters) - RWE will offer to buy Innogy's stake in Czech joint venture Innogy Grid Holding as part of its deal to break up the group with rival E.ON, a document showed on Friday.

After that, RWE will have the option to sell the stake to E.ON, and E.ON will have the option to buy it, E.ON said in the offer document for its 5.2 billion euro (4.55 billion pounds) takeover offer for a minority stake in Innogy.

Last week, sources told Reuters that Australia's Macquarie was interested in some of Innogy's assets, including the stake it does not own yet in Innogy's Czech gas networks unit, potentially disrupting the deal between RWE and E.ON.

(Reporting by Tom Kaeckenhoff; Writing by Maria Sheahan; Editing by Ludwig Burger)