She said pay was not the only issue on the table and due consideration had to be given to other issues. She said settlements in the past under National were either equal to or less than the 2 per cent increases that were on offer now.
Ardern has also revealed the Government has received an application from the Vanguard charter school to become a school of special character.
Education minister Chris Hipkins said a couple of other applications were also believed to be close.
He said Vanguard was the first to apply to become a special character school - the only option for the 11 charter schools as legislation looms to repeal the charter school model.
He said Vanguard ran "a pretty tight ship" and he was not surprised it was organised.
National leader Simon Bridges visited the school this morning.
Hipkins said many of the schools were in leased buildings rather than property owned by the Government. He was not ruling out some financial support in the transition to special-character schools but "it's not an open cheque book".
He said he did not believe the children attending the schools would notice any difference in the change from a charter school to one of special character. He could not pre-empt the decision because there was still criteria to be applied by officials.
There was contingency funding in the Ministry of Education's budget to help resolve property issues for the schools - from purchase to the Crown taking over the lease of property.
Vanguard Military School chief executive Nick Hyde said the school applied for designated character state school status to secure its future.
"My thinking and the board's thinking is how do we make sure the school exists for the next 50 or 100 years," he said.
The application for a designated character school triggers a process in which the Ministry of Education must consult with other state schools that would be affected by establishing a new state school, disregarding the fact that a partnership school already exists.
In Vanguard's case, the school's 186 students come to the Albany site from all over Auckland, from Warkworth to Pukekohe, plus one student who is commuting every day from Te Puke. The school does not provide transport and Hude said most students used public transport.
The former National Government gave Vanguard approval last year to open a second school in Christchurch, but Hyde said the application for designated character status applied only to the Auckland school.
"Our young people are already involved in Auckland, we have staff in Auckland, there are a lot of families involved, so our first priority was securing it," he said. He said Vanguard was "still in negotiations with the ministry" about the proposed school in Christchurch.
Despite a letter from the Catholic Church calling for it to be included in the Royal Commission of Inquiry into abuse in state care, Ardern says she still believes the Inquiry should still focus primarily on the state.
She said she was concerned broadening the inquiry would dilute the focus on state responsibility, but the terms of reference for the Inquiry into state care were still being consulted on and it could not be ruled out.
On a new America's Cup base decision, Ardern said the primary focus was ensuring an economic benefit for New Zealand while minimising the environmental effects - but she would not reveal what the chosen option was.
She said it was an "excellent" base.
Asked about the ball tampering by the Australian cricket team, Ardern said it was right the public were outraged in Australia. She said she had read reports of it happening in the past - including by New Zealand - and it should not be condoned whenever or wherever it happened.
"My personal view would be regardless of what happened where and when, it's just not cricket. It's not fair play."
- Additional reporting Simon Collins