The Prime Minister says the relationship between New Zealand and Australia won't be affected if a new government is elected there.
Australia goes to the polls on Saturday and the Labor government faces a crushing defeat.
Opinion polls continue to show Labor lagging well behind the Coalition, led by Tony Abbott.
Speaking from the Marshall Islands, Mr Key said the trans-Tasman relationship will continue to be strong if Mr Abbott becomes Prime Minister.
Mr Key said the fact Mr Abbott's wife is a New Zealander, from Wainuiomata, doesn't hurt either.