Investa's manager said the funds agreed to raise their offer by about A$120 million to A$5.3485 per IOF unit from an earlier bid of A$5.1485 per unit.
Trading in Investa shares were halted earlier on Wednesday pending the announcement.
($1 = 1.3669 Australian dollars)
(Reporting by Aaron Saldanha in Bengaluru; Editing by Muralikumar Anantharaman)