"Our outgoings are bigger than our income."

That is the daily reality for Manurewa couple Michael and Mina Tamatoa and their four children aged 9, 7, 5, and 11 months.

Their hopes for the Budget are all about their children.

"They are our future," Mina Tamatoa said. "If we can't provide for our children, then our future doesn't look very promising. I think education is top for me."

Michael, 36, works as a rental car mechanic at Auckland Airport. He got a pay rise last month but sees it disappearing fast.

"Now we see petrol is going up," he said. "You're still trying to catch your tail."

Mina, 38, works 20 hours a week for $16.68 an hour as a teacher aide at Rowandale School, which the three older children attend. Her union, the NZ Educational Institute, has lodged a pay equity claim saying teacher aides are underpaid because most are female, and hopes the Budget will lift schools' operations grants to pay for it.

"Our outgoings are bigger than our income," Mina said. "It's our responsibility to try and cater for the shortfall, and that's through food and transport - not just petrol, it's the car's maintenance, the warrant of fitness, everything.

"Sometimes we have to put them on hold, they have to wait, because we have to pay the things that are most important like the mortgage."

They need two cars, spending $70 a week on petrol, because Michael takes one to work and Mina needs the other one to rush back in school breaks to feed her baby, who is cared for by an uncle while she works.

The family will gain a whopping $120 a week when family tax credits go up on July 1 - a lot more than the extra $4.70 a week that they will likely pay for petrol when national and regional taxes go up later this year.

Anything more in tomorrow's Budget looks set to be small change by comparison.