* Existing offer stands at NZ$7.80/share

* Shares halted till update on talks or Monday - NZX

April 15 (Reuters) - Shares in New Zealand's Tilt Renewables Ltd were halted on Thursday as the wind farm operator held talks for a better takeover offer than the NZ$2.9 billion ($2.07 billion) deal it agreed to last month.

The existing offer, at NZ$7.80 per share, was for selling the company's Australian assets to Powering Australian Renewables (PowAR) and its New Zealand assets to its second-largest shareholder Mercury NZ.

Interest in Tilt comes amid a push from companies and investors towards clean, renewable energy and will give the buying consortium access to the company's 20 wind farms that are operational or under development.

The company's shares will remain in a trading halt pending an announcement on the discussions, or until Monday, New Zealand's bourse operator said.

The stock has rallied more than 17% since March 15, when the first deal was announced.

AGL Energy, which owns 20% of PowAR, had said it would contribute A$341 million ($263.3 million) towards the deal.

Tilt's largest shareholder, Infratil, said on Thursday it awaited Tilt's update on the outcome of the talks.

AGL declined to comment, while Mercury did not immediately respond to a request for comment. Investment manager QIC, which owns the rest of PowAR, also declined to comment.

Mercury's shares fell as much as 4.2% in their worst session more than three weeks, while Infratil cut early gains to trade about flat by 0215 GMT. ($1 = 1.4013 New Zealand dollars) ($1 = 1.2952 Australian dollars) (Reporting by Nikhil Kurian Nainan, Shruti Sonal and Shashwat Awasthi in Bengaluru; Editing by Subhranshu Sahu and Shounak Dasgupta)