Meridian Energy reported record full-year earnings, boosted by higher power prices and generation volumes and a growing customer book in Australia.

The country's biggest electricity generator said net profit jumped 68 per cent to a record $339 million in the year ended June 30.

Earnings before interest, tax, depreciation and changes in financial instruments rose 26 per cent to $838m, also a record.

"The results reflect a record level of hydro generation in New Zealand, and higher wholesale prices as a result of supply interruptions at the Pohokura gas field, and periods of low hydro inflows," chief executive Neal Barclay said in a statement.


The performance enabled the company to lift total dividends to the government and shareholders by 11 per cent, while overseeing a decrease in average energy prices for households and small businesses, he said.

The company's New Zealand power stations delivered 13,570 GWh of electricity in the period, 8.3 per cent more than a year earlier. Low lake levels late last year and tight gas supplies meant it received an average $123.30/MWh for that output, up from $83/MWh a year earlier.

Contracted retail sales rose 4.3 per cent to 6,240 GWh, although its average retail price was marginally lower at $104.80/MWh.

Volumes sold to the Tiwai Point aluminium smelter, the firm's biggest customer, were almost 6 per cent higher at 5,310 GWh after the smelter restarted a potline in December that had been shut since 2012.

Retail volumes in Australia were marginally higher than the year before, while generation volumes were 31 percent higher, reflecting the firm's purchase of Trustpower's three hydro schemes there early 2018.

Ebitdaf from the Australian business rose to $64m, from $44m a year earlier, while other earnings – mostly from the Powershop UK business and technology arm Flex Federation – rose to $18m from $17m.

The company will pay a 10.72 cent final dividend and a 2.44 cent special dividend on October 16 to investors registered at September 30. That takes the full-year payout, including special dividends, to 21.30 cents, from 19.20 cents a year earlier.

Meridian shares closed Friday at $4.77, up 45 per cent from a year ago.