Salvation Army analyst Alan Johnson said the Budget's $240 million a year package created "a potential momentum that we need to build on".
"We think this Budget has broken the mould. Finally after a long, long time, we don't have to have incomes for the poorest New Zealanders tied to the consumers price index and nothing else," he said.
But he added: "We are fearful that as we move into surplus, the narrative will change. It will be about tax cuts," he said.
"It will not be what we can do with the surpluses to build a better New Zealand, it will be what the Government cannot do. That is a narrative we have to look out for and object to."
Auckland University economist Susan St John said New Zealand still had a yawning "social deficit" with 180,000 children living in hardship, high rates of domestic violence and child abuse and high rates of poverty-related illnesses.
"In a way this Budget is tokenism. What we really want is resolution of the social disaster of child poverty," she said.
She argued that the Government's net debt was already low and tax had fallen from 34 per cent of the economy in the 1990s to a projected 30 per cent.
"Government is still pointing to tax cuts in 2017 which we should resist at all costs," she declared.
"What we have is plenty of room to raise taxes and meet the required social spending. We should not be fobbed off by any politician telling us otherwise."
Video: Economics editor Brian Fallow - This is a tight-fisted budget:
Paediatrician Innes Asher said hospitalisation rates of Maori and Pacific children with poverty-related illnesses such as bronchial and skin diseases increased 70 per cent from 1996 to 2009 in a period when the rates for European children remained low and stable.
"If the tables were turned, if the rates of those conditions were escalating for NZ Europeans and rock bottom and stable for Maori and Pacific, would the country have taken a different course of action?" she asked.
She welcomed last year's Budget decision to extend free doctor's visits and prescriptions for children up to age 13 from this July, and urged the Government to use future surpluses to extend free healthcare to age 18.
"Thirteen to 18-year-old children suffer from depression, especially if they are in poverty. They suffer from asthma and skin infections at rates higher than younger children," she said.
Dr Hirini Kaa of the Maori child advocacy group Te Kahui Mana Ririki said yesterday would be remembered by future historians as "a real significant change" towards greater social justice, and an extra $25 a week or $1300 a year would make a huge difference to Maori families in poor areas such as the East Coast.
But he said injustice in New Zealand was still about racism, with Maori and Pacific people at the bottom of every indicator.
"It's not post-colonial. Colonialism continues unabated. That's why Maori are at the bottom," he said.
He said New Zealand should celebrate the Treaty of Waitangi settlements which began with the $170 million Waikato-Tainui deal signed 20 years ago today, but that was just a start.
"Yes, there is inequality within Maoridom, and there is injustice within Maoridom, and yes, we have to be careful about that. But the challenge is it's going to take decades until Waikato-Tainui are going to find the economic rangatiratanga that they used to have and was taken off them."
Video: Budget 2015 - Public reaction
