South Australia Power Networks said on Thursday that it would pay more than $15 million in compensation to customers who were subject to unnecessary lengthy blackouts in 2016.

More than 70,000 customers were expected to be given the payment, Xinhua news agency reported.

It was reported that more than 150,000 properties in South Australia were left without power on December 28, after a vicious storm cell felled power lines and trees. 

It was the second major blackout to hit the state in three months.

South Australia Power Networks spokesman Paul Roberts described the storm and its trail of destruction as the worst the company had experienced in 30 years.

"It was probably about three times worse than any previous storm we've experienced, both in terms of the guaranteed service level payments we'll have to make, and the minutes of supply lost for customers," Roberts said.