The Government's expected to have to borrow another six to seven billion dollars.

That's on top of $7 billion it's already expecting to borrow.

But ANZ Chief Economist Cameron Bagrie said that's not the end of the world.

However, he says if net debt starts to move up, that's going to be a red flag for the ratings agencies.

"Private sector debt is very high, so we need to be squeaky clean on one side of the ledger for them to forgive us on the other side."

The bank has compared where it thinks the economy is tracking, with Treasury's pre-election economic and fiscal update and Bagrie believes growth is 0.5 or 1 percentage points below Treasury, which knocks about a billion dollars off tax revenue.

He said the Government's going to need more money for the 2019/20 Budget.

"You roll the numbers together and it looks like we will end up with an operating surplus of around $4 billion, as opposed to $6 billion. Now the glass half full interpretation of that is, $4 billion's still a pretty good ward chest, you're still putting money in the bank."

Cameron Bagrie says if we see net external net and our fiscal position move in bad directions, that's going to create tension.

But he says we have a bit of a buffer at the moment.

LISTEN ABOVE AS CAMERON BAGRIE SPEAKS WITH MIKE HOSKING