Prime Minister John Key's opening address of the National Party election campaign was disrupted by chanting protesters shouting "stop the war on the poor."
About four protesters chanted as they were escorted out of Auckland's Sky City Convention Centre by police.
They returned to a group of picketers outside the venue, where Mana's Waitakere candidate Sue Bradford was speaking through a megaphone.
As they were being escorted out, Mr Key said "they're welcome to come to our launch because they haven't got one of their own."
At the launch, Mr Key announced that National would put the estimated $5 billion to $7 billion proceeds from partial asset sales into a special fund, the Future Investment Fund.
He said the fund would run for at least five Budgets and would fund new assets like major hospital redevelopments, new schools and transport projects.
"We will set a high bar for projects to be funded out of the Future Investment Fund and the case for these projects will have to stack up," he said.
The spending would be transparent.
"In this way the public can be assured that the proceeds of mixed ownership are not being lost."
He said the first priority for the fund would be education and $1 billion of the fund would be tagged to modernise and transform New Zealand schools over five years.
Mr Key's announcement is an acknowledgement that asset sales have the potential to erode National's healthy lead in the polls.
National's plan to sell up to 49 per cent of four energy companies, Mighty River Power, Meridan, Genesis and Solid Energy, and to sell part of its stake in Air New Zealand is its most unpopular policies according to previous polls but it has not dented its support.
Now, however, as the campaign for the November 26 election begins, Labour is making opposition to asset sales a central feature of its campaign.