UPDATE 1-NZ's Infratil looking at some Shell NZ assets

* Infratil in talks with Shell over NZ assets

* Deal expected to be worth around NZ$1 billion (Adds detail)

WELLINGTON, Nov 3 (Reuters) - New Zealand infrastructure investor Infratil Ltd (IFT.NZ) is in talks with Royal Dutch Shell (RDSa.L) over acquiring the oil company's local downstream and refining businesses, in a deal expected to be worth about NZ$1 billion ($710 million).

Infratil said on Tuesday it had joined with the New Zealand state superannuation fund to negotiate with Shell for the assets, including a 17 percent stake in the New Zealand Refining Company (NZR.NZ), and the retail and distribution arms of the business.

The consortium has submitted a non-binding proposal and would make no further comment while negotiations are ongoing, Infratil said in a statement.

Shares in Infratil last traded down 1 cent at NZ$1.64. So far this year the stock has gained 1 percent against a 17 percent gain for the benchmark NZSX-50 index .NZ50.

Local media have reported that the Shell assets could be worth about NZ$1 billion, and have annual revenues of between NZ$100 million and NZ$150 million. Shell is one of the largest players in the energy market in New Zealand, with a network of more than 200 petrol stations and storage and pipelines. It said in February it was considering divesting some or all of the assets.

It also has stakes in many of the country's major oil and gas projects such as Maui, Kapuni and Pohokura, which it will retain.

Infratil's main investment is a 51 percent stake in Trustpower (TPW.NZ), and it also has energy businesses in Australia, airports in New Zealand and Europe and New Zealand's biggest bus company.

In an interview in July, Infratil's chief executive Marko Bogoievski said the company as on the lookout for acquisitions., The NZ government's superannuation fund, set up in 2003, invests in long term assets to help pay for future pension costs. It has funds under management of around NZ$15 billion. ($1=NZ$1.40) (Reporting by Adrian Bathgate)