Big Wednesday jackpot winners' advice to overnight millionaires

A pair of best friends who split a $12.3 million Big Wednesday win last year have some advice for tonight's potential jackpot winner.

The $30 million Powerball jackpot is the biggest its been since 2013, when a second division winner took home an additional $33 million.

One half of last year's lucky pair, who live in the South Island, spoke to the Herald on the condition of anonymity.

She and her friend have paid for their own and their children's mortgages with their winnings, and they advised any winners tonight to be up front with their families if they win.

"Let your family know that you've won and be clear about how you want to help them - and how much - at the same time.

"Being open and honest with everyone makes life so much easier."

The pair had been on holiday in Auckland and bought the winning ticket from St Luke's in May.

After checking the numbers online, one of the pair began to realise what that ticket held.

"We usually checked our tickets together over morning tea the day after the draw.

"However when we won, I did things slightly differently in that I'd jumped online to write down the winning numbers and then thought 'maybe I'll just check one number' and then lo-and behold we had it.

"Then I couldn't help myself, so I had a peek at the second number - we had it too. The next thing I knew I'd checked all of the numbers and realised we had the lot - we had the winner."

The first thing she did was call her friend - but she started crying so hard her fellow millionaire thought something terrible had happened.

"I eventually managed to splutter through my tears and tell her we'd won the lottery. We really couldn't believe it, it's an unbelievable thing."

She recommended seeking advice from third parties about how to spend the money.

As well as paying of loved one's debts, the woman said she and her husband have indulged in plenty of luxury travel.

"Travel has been our biggest indulgence, for sure. My husband and I treated ourselves to a luxury weekend in Singapore - flying business class all the way.

"It was a real treat for us and we truly did feel like millionaires the whole time."