EVEN the richest walking among us aren't satisfied with Prime Minister Scott Morrison's "fair dinkum" sell on power prices.

Multi-billionaire tech ­entrepreneur Mike Cannon-Brookes has slammed Mr Morrison on Twitter over a recent online video that promises better power prices for Australians.

He demanded a "rallying cry" for Australians concerned about our energy future, saying he's "not sure (Mr Morrison) knows what fair dinkum means".

The Atlassian co-CEO and co-founder is worth an estimated $5.16 billion. The Young Rich Lister used his tweet against the Prime Minister to launch a logo competition for the new renewable energy initiative Fair Dinkum Power.

In 24 hours, the logo with the most votes will win, but it's not yet known where it will end up.

The billionaire's rant followed a video from the Prime Minister last week about lowering the nation's energy prices.

"We've got get electricity prices down," Mr Morrison said in a video released last week. "I met Avril and Colin this morning. Colin served in our defence forces and is a defence force pensioner. Avril's gone back to work to pay for the bills."

He then holds up a sheet of paper.

"This is their electricity bill. You can see it's paid, but they are paying too much," he says, without revealing how much they're paying.

"I look through your comments and you say, 'Well, how you going to do it?' " Mr Morrison continues. "We're going to get the electricity companies in line. We're going to do it with new laws and new rules, which means they can't rip you off simply by you being a loyal customer.

"If you stay with them you shouldn't be penalised for that. We're going to stop the price gouging and have tough penalties for the big electricity companies if they try and do that.

"And thirdly, we're going to force them to put more fair dinkum, reliable energy, power, into the system."

"Renewables are great," he continues. "But we're also needing the reliable power when the sun isn't shining and the wind isn't blowing. That's what keeps the lights on. Lower electricity prices. Meeting our emissions reductions targets. And ensuring the lights stay on."

Energy Minister Angus Taylor last night defended the government's policy.

"The government stands arm-in-arm with the hardworking Australian businesses and families who want to see lower power prices,'' Mr Taylor said.