Mercury NZ and infrastructure investor Powering Australian Renewables (PowAR) have lifted their offer for Tilt Renewables to $8.10 a share from $7.80 in response to a reported Canadian bid.
Separately, Tilt's majority shareholder Infratil said it supported the offer, which values its stake at $2 billion.
Tilt's shares last traded on the NZX at $7.60.
The revised bit comes after Australian media speculated that Canadian pension fund CDPQ may have launched a competing bid for the wind power specialist, which has extensive assets in New Zealand and Australia.