Conservative Party leader Colin Craig says he would not form a Government with National unless it agreed to introduce binding referenda.
Mr Craig confirmed the party's bottom line for potential coalition talks at its annual meeting in Auckland this afternoon, attended by around 120 delegates.
In his keynote speech, he said: "We are not playing a mystery game. We are being upfront with the electorate.
"The thing that we want, that will be required if a party wants our support, is that they are going to need to agree to a change whereby that the people of this country have the right on those rare occasions ... to tell the government where to go and what to do."
He later told reporters it may not be enough for National to step aside and give him an uncontested race in the East Coast Bays seat, where he is a candidate.
"We'd want to see referendum get across the line, that's the one thing that matters for us."
Conservatives would not go into coalition or enter a confidence and supply agreement unless this condition was met.
Mr Craig said: "We're not going to be unconstructive, but in terms of getting our full support, that is our bottom line. That is what we want to achieve.
"While some people might see that as a difficult, I think it's also a positive in that we're a known quantity. People know we're not demanding a Cabinet seat, that we're not demanding portfolios or anything else."
He said he would be willing to negotiate the terms of the policy with National.
Conservative wanted referenda to be binding if they were supported by two-thirds of voters, but it might accept a different requirements.
Before entering politics, Mr Craig helped organise a citizens-initiated referendum in opposition to anti-smacking legislation, which was supported by 88 per cent of voters.
New Zealand First leader Winston Peters said earlier today that if National offered Mr Craig a deal in East Coast Bays, he may consider running for the seat.
Mr Craig said he did not believe Mr Peters would run, and if he did, Mr Peters would place third.
"I don't think he would, and I'm not at all worried if he does. [He would place] behind me, no question about that."
Mr Craig took the stage for his keynote address with wife Helen after a performance of "Pokarekare Ana" and Leonard Cohen's "Hallelujah" by young singer Tayla Alexander.
The recurring theme in his keynote address was that Government had become too large, too proud, and had failed to listen to public opinion.
Conservatives wanted to cut the number of MPs from 122 to 99, to reduce the number of public servants, and to cut red tape and bureaucracy which had contributed to housing pressures in Auckland.
Mr Craig said "moral busybodies" and an "activist minority" had led to policies which were opposed by a large section of the population - in particular anti-smacking laws which led to "good parents" being persecuted.
"Indeed today we have good parents being investigated, on average two a week, and while that's going on real child abuse is going on unabated."
The Conservative leader was visibly moved when speaking about abuse victims, later saying it was because of his personal experience of close friends who had been hurt as children.
Mr Craig defended the party's key election policy of scrapping Maori Parliamentary seats, saying it was neither cynical nor racist.
"We will only be a great nation when can see beyond the colour of our neighbour's skin."
He also took a shot at his potential coalition partner National.
"Did you think that the highlight of the National Government's second term would be ... increasing the number of pokies at SkyCity, redefining marriage, and ... the record amount of debt they've got us into?
"It's the time for us. It's the time for what we stand for. New Zealanders want it."
Mr Craig left the stage to a standing ovation and the sounds of "Stand by Me".