On the day of a record $26 million Big Wednesday Lotto draw, gambling counsellors are calling for a lower limit on lottery jackpots.

Problem Gambling Foundation chief executive Graeme Ramsey wants the $30 million cap on jackpots - doubled from $15 million in 2005 - to be cut to $12.5 million, which is below the level at which the public usually gets excited.

Mr Ramsey said big jackpots lured more people into gambling, "fuelling a gambling environment in New Zealand where only a few are real winners" at a cost to the whole community.

Foundation analyst Graham Aitken said jackpots usually grew by about $2 million a week in the early stages.

But they took off and started growing by $5 million and $6 million a week once they reached about $15 million.

Mr Ramsey said the cap should be fixed below that so people were not lured into spending more than they could afford.

"Surely $12.5 million as a prize is big enough for anybody in this country," he said.

Tonight's jackpot features $25 million in cash plus $1.7 million in luxury prizes including two sports cars, a boat, a credit card, overseas travel and a bach.

If unclaimed, it will jackpot to $30 million next week.

If it is still not struck, the pot will be shared among second division winners the following week.

But the Lotteries Commission appears happy to see jackpot limits go even higher.

In a November briefing paper to then Internal Affairs Minister Richard Worth, the commission said it was looking into joining a proposed "world lottery" headed by Britain's National Lottery.

"It is very likely that participation would entail lifting the current $30 million prize limit set on our games," the paper said.

It is understood the proposal is still being evaluated.

New Internal Affairs Minister Nathan Guy - who was sworn in to replace Dr Worth yesterday - declined to comment.

Lotteries Commission spokeswoman Karen Jones said 1.98 million tickets were sold for Big Wednesday last week, compared to 500,000 in a normal week.

"We must assume that many players bought two tickets to cover their heads and tails options, so this does not translate to 1.98 million customers," she said.

But even if the average was two tickets each, that means about a million New Zealanders, or about a third of the adult population, bought tickets.

A similar $30 million jackpot in the Saturday Powerball game last October pushed total Lotto sales up 19 per cent to $442 million in the second half of last year, and the combination of that plus the current Big Wednesday run is expected to push sales for the year to June well over the budgeted $770 million.

"It's a very unusual situation this financial year because our two big games have both been on very long runs that are designed to happen only once in five or six years," Ms Jones said.

Lotto retailers yesterday reported extraordinary interest in today's Big Wednesday draw.

Nigel Bird of Beach Haven Video and Lotto Centre said customers queued for an hour from 5pm last Wednesday.

"If Powerball gets over $17 million they start to queue up on the street. That just seems to be the figure."

Tonight's draw will be screened on TV1 at about 8.20pm.