The big one: $38 million up for grabs in tonight's Lotto draw

Do you have the lucky numbers?

Lotto's top Powerball prize has hit $38 million and if won by a single person, will be the second-largest prize won in New Zealand history.

Last November, a young couple from Hibiscus Coast took home $44m in a must-be-won draw.

It was the single biggest win since Lotto started in New Zealand in 1987.

Some of the country's biggest wins have gone to people who were a part of a Lotto syndicate - either within their family, among friends or colleagues at work.

Lawyer Steve Cullen told Newstalk ZB's Mike Hosking this morning that those involved in such groups needed to make all rules and arrangements very clear.

"Perhaps write a name of a syndicate on the rear of the ticket and then have a collateral contract - some sort of document that accompanies it that says these are the members of this syndicate who intend to share in the proceeds of this ticket equally.''

He encouraged people to make use of technology - by taking a photo of the ticket and sending it to members before the draw.

People also needed to have a clear understanding about the rules around paying for the ticket each week and particularly about what to do if someone did not pay their share of a winning ticket.

"The less the intention of the parties is that you would all share whether you are there or not, that's your difficulty,'' Cullen said.

"That's where you get into confusion and that's where people wind up being excluded from proceeds and arguments develop.''

If tonight's Powerball is not struck, the prize has the potential to reach a must-win jackpot of $50 million; a change announced by Lotto NZ this year.