Infratil has reported a loss of $31.4 million in the six months to September, after writing down the value of assets.
In the same period a year earlier, the infrastructure investor made a $7.3 million profit.
The Wellington-based company has been selling underperforming assets and reducing debt in response to the economic downturn, with an increasing focus on energy on both sides of the Tasman, airports and public transport.
The company says talks to buy Shell's refining stake and petrol stations are at an advanced stage, and it will be disappointed if a deal is not struck.
Infratil chief executive Marko Bogoievski says Infratil has the balance sheet, and he thinks it can get better returns than the oil giants have done.
He says they have invested heavily in exploration, rather than focussing on optimising New Zealand returns.
Infratil expects lower operating earnings of between $355 million and $370 million, reflecting lower gas prices at its Australian energy arm and the cost of industrial action at NZ Bus.
Mr Bogoievski also says the company's relaxed about its underperforming British airports, as it turns its attentions to opportunities in Australasia.
Infratil recently sold its interest in Germany's Luebeck Airport for $65 million, and some analysts now expect it to sell Glasgow Prestwick and Kent airports
Mr Bogoievski says Infratil got them cheap, but admits they may be taking up more time than warranted.