Gas price spikes, due to rising LNG exports, are squeezing profit margins for retailers like AGL, who have to buy gas to supply customers.

AGL reported a 3.7% rise in underlying profit for the six months to December to AUS$389 million.

AGL said its full-year underlying profit would land in the upper half its forecast range of AUS$720 million to AUS$800 million, up from AUS$701 million last year.

To help deal with a potential gas supply shortage in southeastern Australia, AGL is considering building a terminal to import LNG – once an improbable idea with the country set to become the world's biggest LNG exporter by 2019.

The company expects to make a final investment decision by June 2018. It is considering building a floating LNG regasification plant or a plant onshore.

AGL's shares rose as much as 4.6% to a record high of A$24.05 after the result.