"The whole is greater than the sum of the parts," he said.
He welcomed other moves in the Budget to extend subsidies for insulation and healthy housing, increase social housing subsidies and boost support for beneficiaries to move into work.
"They are good things to do," he said.
"But they are ad hoc. I can't see the wider plan to reduce child poverty. I can't see a wider plan to reduce homelessness and crowding here."
Christian social services say they are "saddened" that the Budget didn't raise benefits for New Zealand's poorest families.
Council of Christian Social Services executive officer Trevor McGlinchey said he had hoped that the Budget would build on last year's surprise decision to raise benefits for families with children by $25 a week from last month.
"I was really disappointed that the Government didn't build on that start last year," he said.
"There was an opportunity to take a real courageous track and make a difference. That didn't happen, and that is quite saddening."
He welcomed extra spending on the new "super-CYF" children's ministry and on increasing income-related rent subsidies for social housing tenants, but he was disappointed that there was no capital funding to actually build more social housing.
"What would have been really good would have been an injection of funding into the community housing sector so that they could actually build more social housing," he said.
He was also disappointed that the Budget still did not provide any inflation adjustment for social service agencies, which have not had an inflation adjustment to their contracts since 2008 - apart from the extra money for the children's ministry.
"Further social support through community-based organisations is needed, and the Budget does not give me any indication about how those supports can be delivered," he said.
"There is some Whanau Ora funding and that's great, and there is funding for those children in care, but our organisations are working with much more complex families, and many more of them, and need support, and that's not there."