One of the warmest starts to winter on record prompted fewer people to turn on their heaters, but Australia's biggest energy retailer still enjoyed a better-than-expected year.

Origin Energy dusted itself off from July's data breach debacle on Thursday as it briefed investors on another strong year, adding that it's cashing in on an energy transition that's far from over.

Going big on batteries is making up for slimmer takings from its gas fields and warmer weather driving consumption down on the home front.

"There's still a long way to go in the transition," chief financial officer Tony Lucas told an earnings briefing.

"Don't expect winter to have disappeared out of Australia in its entirety."

The eastern states have had their second-warmest winter since records began in 1910, with Sydney smashing its June average temperature record and Melbourne posting its warmest ever night for that month.

It has been 15 years since eastern Australia had a colder-than-average June, but Origin didn't expect 2026's record-breaking conditions to endure.

"You'd expect the weather to ... revert at some stage," Mr Lucas said.

But higher temperatures will likely endure until early 2027, according to the Bureau of Meteorology, due to a strong and persistent El Nino climate pattern, which causes hotter and drier conditions to settle across Australia.

Hotter summers are also helping to flood the market with solar energy, meaning Origin had more trouble offloading power generated by gas and coal, which is still its biggest electricity source. 

Nevertheless, it pocketed $1.7 billion in underlying pre-tax profit from its electricity business in 2025/26 - a 21.2 per cent increase - as its retail customers forked out about 4 per cent more for electricity on average.

Origin is also cashing in on the energy transition, having brought on enough battery capacity to power all the homes in Brisbane or Perth in the year ended June 30.

It expects the strategy to supercharge underlying earnings from selling power to up to $1.85 billion in the coming financial year.

"In the summer, where you've got plentiful renewable output, particularly with solar, then battery (power) ... will do that daily shifting of supply," Mr Lucas said. 

"We do see gas having to play a role in those longer durations as renewables come on, but I just think we haven't seen that this winter."

The energy giant's underlying profit slumped more than 22 per cent to $1.2 billion, but that still beat consensus estimates and was tempered by a 6.2 per cent jump in bottom-line net profit to $1.6 billion.

The good tidings were welcome after July's data breach, which exposed the personal details of almost one million of Origin's current and former customers.

Origin was accused of responding sluggishly to the hack, which potentially exposed some clients' bank and credit card information.

"We've taken steps to secure our systems, we've been working with cybersecurity and forensic specialists," chief executive Frank Calabria said.

"The matter does remain subject to an ongoing criminal investigation." 

Origin shares were up almost five per cent to $11.80 in afternoon trading, and at their highest level since early May.

Origin declared a final dividend of 30 cents, taking the total for the year to 60 cents.