The economy will be in sharp focus today.

Treasury will be looking at the state of the nation's books and the Finance Minister Grant Robertson will deliver his Budget Policy Statement which is a precursor to his Budget next year.

Robertson said the showpiece today will be the Government's much talked about families package.

"We are talking about reversing the previous government's proposed tax cuts and replacing them with some targeted assistance to families, particularly around children. We think it's a big development and an exciting package."

He said they have had a short time to put everything together but he said today's financial news will give people confidence.

"Our priorities will be laid out there. We are also able to show how we have costed and afforded our 100 day plan policies and in particular the Families Package which is the big remaining element of that."

Robertson said he's looking forward to his first big test.

"It is a big day in my calendar and only seven weeks in we have had to work hard to get ourselves to the position of being able to say, here's what we've done in our 100 days, how much it cost, and here's what we are planning to do in Budget ."

He said he is confident the public will like what they hear.

"What you will see today is that we can in fact afford the promises that we have made. You will be able to see that we can afford to do that and have some head room as well."