(Adds details on deal, background on Blackstone activity) May...

(Adds details on deal, background on Blackstone activity)

May 28 (Reuters) - Australia's Investa Office Fund (IOF) (IOF) said on Monday it has received a A$3.08 billion ($2.3 billion) unsolicited non-binding buyout proposal from the Blackstone Group BX.N .

The directors of IOF manager Investa Listed Funds Management (ILFM) said they plan to unanimously recommend the offer, which equates to a distribution adjusted price of A$5.15 per unit.

The offer represents a 13.2 percent premium to IOF’s ex-distribution closing price of A$4.55 per unit on Friday, they added. ILFM's directors and Quartz Holding (NQ) Pte, a Blackstone affiliate, have entered a process deed setting out the offer's terms.

The bid marks a move deeper into the Australia-New Zealand real estate market for the U.S.-based private equity giant.

Less than two weeks ago, it struck a NZ$635 million ($439.4 million) deal to buy an office portfolio in Auckland which was co-held by Goodman Property Trust (GMT) and Singaporean investor GIC.

A Blackstone unit was said to be the buyer in the sale of a Sydney office building earlier this year. The building, which sold for A$205 million ($154.9 million), was owned by a unit of indebted Chinese conglomerate HNA Group. ($1 = 1.4453 New Zealand dollars)

($1 = 1.3236 Australian dollars)