Both ratings agencies had taken some trouble in their statement to mention that the Government books were on the right track.
Mr Key also claimed that at a meeting in New Zealand about a month ago, Standard & Poors said a downgrade was more likely under Labour.
"It did go on to say ... that if there was a change of Government, that downgrade would be much more likely.
Standard & Poors Sovereign rating analyst Kyran Curry could not be reached for comment last night.
Mr Goff said after the House that Mr Key should tell homeowners the truth.
"He should stop trying to wriggle out of taking responsibility for his abysmal handling of the economy."
The downgrade put New Zealand on a par with Spain - a country whose economy had been repeatedly described by National as in trouble.
Mr English told Parliament that the view of New Zealand by the agencies was determined by its large external liabilities most of which was private debt.
From 2005 to 2008 New Zealand's current account deficit was over 8 per cent of GDP which was almost a record for any country and households were spending about $1.11 for every dollar they earned.
By every measure the outlook had improved over the last three years, English said. The balance of payments deficit had halved, households were saving again. New Zealand would have positive savings rates for the first time in 20 years. Foreign liabilities had fallen by $16 billion over the past two years.
"We have focused on getting through the recession while encouraging more saving and exporting and discouraging excessive property speculation, out-of-control Government spending, and too much debt."