"We must have strong voices saying that those choices are wrong and offering an alternative."
She and co-leader Russel Norman said it did not mark a shift for the party in terms of its criticism of the Government - their comments reflected the frustration of many communities following Budget 2012, in particular with regards to education changes.
Mrs Turei directly attacked Mr Key for undermining the state school system despite previously speaking of the importance of his own public education at Burnside High School.
"I'm amazed that the Prime Minister could be so blatant in saying that his pathway out of poverty was education and then so clearly stripping away that pathway today.
"He has cut back on public schools. He has increased funding to private schools because he wants his kids to have better access to better education and small class sizes."
In her speech, Mrs Turei called for a cross-party political consensus on child poverty, similar to the Government's informal agreement on elderly poverty.
While poverty among the elderly in New Zealand was nearly the lowest in the OECD, child poverty was among the worst in these nations. Achieving a cross-party consensus could be difficult because the gap was widening, not closing, between the Green Party and National.
"It's true that National has become far more right-wing and ideological in its policy in this term of Government than they were in the last, and that does open a bigger gap between the Greens and them," Mrs Turei said.
She said the Government needed to be put under pressure because they had not prioritised children in Budget 2012.
Much of the party's "Growing the Greens" conference focused on how it would approach governing the country, most probably in a coalition with Labour.
Asked whether the growth of the Green Party would make it more difficult to stick to its principles, such as refraining from personal attacks, Mrs Turei said: "No. There are different challenges for a party in Government than in Opposition, and we are planning for this.
"We will be ready to go into Government at any point, and we will have our party systems and our policy systems set up so that we aren't in breach of the principles we find most important."
GROWING INTO A POLITICAL FORCE
The Green Party has revealed that its monthly donations have tripled in the past six years, adding more fuel to its belief it is transforming from a minor party into a political force.
Departing co-convener of the party Roland Sapsford - the equivalent of a party president - said that since the Greens' general election disappointment in 2005, the party had become a more professional group that was attracting greater financial support.
In June 2006, the party gained $5000 a month in automatic payments. Now the party is collecting $18,000 a month, despite difficult economic conditions.
Mr Sapsford said that in the 2005 election, when the party lost three seats, Greens raised $600,000 and were in debt of $35,000 six months after the election.
In the 2011 election, the party raised more than $1 million, and the party was now in surplus of $335,000, Mr Sapsford said.
The "Growing the Greens" annual meeting in Silverstream, north of Wellington, focused on consolidating the historic election result last year, and generating further growth.
At last year's conference the party raised the problem of its weak Auckland presence.
It has since expanded its number of Auckland MPs from one to four and opened a "national issues office" in the city, led by former Cabinet minister Laila Harre.
The Green volunteer army has grown to 2000, most of whom were collecting signatures for petition against asset sales.
The party has also formed Pacific Greens to encourage Polynesian support. The Greens' party vote was poor in south Auckland electorates with large Polynesian populations, which were typically Labour strongholds.
