Both sides of the debate over this week's referendum on whether smacking should be a criminal offence are openly flouting the $50,000 spending limit by disowning their own allies.

Larry Baldock, the Kiwi Party leader who initiated the petitions to hold the referendum, said yesterday his $50,000 radio advertising campaign for a "No" vote was not part of the official "Vote No" campaign.

"I haven't been promoting the 'Vote No' site or the 'Vote No' coalition," he said.

And Green MP Sue Bradford, whose bill banning the use of physical force for correction sparked Mr Baldock's petitions, said a party leaflet on "Why we're voting yes" was nothing to do with the "Yes Vote" campaign.

"We are not part of that coalition," she said.

"When we did our recent Green Party leaflet on the topic, we were very careful to keep the 'Yes Vote' off it."

Both sides appear to be deliberately risking the $20,000 maximum fine for breaching the $50,000 limit on each side of the campaign around a citizen-initiated referendum, which covers the full year up to the close of voting on Friday.

Family First spokesman Bob McCoskrie, who manages the "official" Vote No website, said Family First had an annual budget of $200,000 to $250,000, much of which had been spent on a series of full-page advertisements on the smacking law over the past year.

But he said most of the advertising was nothing to do with the referendum.

"It's been about getting a law change, educating the public about what's been going on with it. We've been trying to avoid the referendum," he said.

Yes Vote spokeswoman Deborah Morris-Travers said her coalition had taken advice from the Chief Electoral Office and had been careful to keep within the $50,000 limit.

She said Government funding paid to Yes Vote coalition members such as Barnardos and Plunket was tagged to specific programmes and was not being diverted to the referendum campaign.

"Our funders for this campaign have been private citizens and trusts who are concerned to see that the child discipline law remains in place," she said.

But Mr McCoskrie accused her members of promoting the current law through their regular taxpayer-funded programmes.

"We've had evidence of people attending a Plunket course and being lectured on voting yes," he said.

"I had people who contacted me from down in Christchurch who went to a WEA course and were being spammed with Yes Vote material.

"I've just learnt of Health TV, a Government-funded service in doctors' waiting rooms, where someone sat through a lesson on why you shouldn't smack."

Chief Electoral Officer Robert Peden said he had received only one complaint about referendum advertising, which was about the lack of an authorisation statement.

He declined to comment on what either side was doing until their expense returns were filed by September 25.

"The returns must list where every advertisement was published or broadcast and the cost of every advertisement," he said.

"The expenditure limit applies to advertising which is used, or appears to be being used, to promote one of the answers to the referendum question, and is published or broadcast during the period from August 26, 2008, to August 21, 2009.

"It is an offence for any person, either alone or in combination with others, to knowingly spend more than the $50,000 expenditure limit."

Mr Peden said 1,330,900 votes had been received by last Thursday, or 44 per cent of the 3,002,968 electors on the roll.

Both sides expect the final turnout to be around 60 per cent - higher than the 49 per cent who voted in the 2007 local body elections, but below the 80 per cent turnout in the country's only previous postal referendum, on superannuation, in 1997.

* Calling time

Voting in the referendum asking, "Should a smack as part of good parental correction be a criminal offence in New Zealand?" ends at 7pm on Friday.

Votes should be in the mail by tomorrow to reach the Chief Electoral Office in time.

A preliminary result is expected at 8.30pm on Friday.

The final result, including overseas votes, will be declared at 5pm on Tuesday.