Labour leader Phil Goff says a downgrade in the country's credit-rating outlook is an embarrassment for Prime Minister John Key.
The international ratings agency Fitch says it may downgrade New Zealand's AA+ rating because of the large current-account deficit, rising debt levels and poor household savings.
A central theme of this year's Budget was the need to avoid a rating downgrade - and indeed, another influential ratings agency, Standard and Poor's, then upgraded its outlook for New Zealand from negative to stable.
But Mr Goff says the downgrading of Fitch's outlook should have Mr Key rethinking Budget cuts made to KiwiSaver and the New Zealand Superannuation Fund.
He says those cuts make New Zealand more reliant on borrowing from overseas.
Mr Key denies that, however, saying he doubts whether Fitch's move will impact on the country's ability to borrow.
He says the Government is addressing issues like the current- account deficit by focusing on improving productivity and boosting exports.