The HSBC bank says the New Zealand economy is expected to grow by an average of 3.1 percent annually over the next four decades.
It says this will mean New Zealand is the only developed country to be labelled a growth country - unlike other western states such as Australia and Canada.
Most countries with really high growth rates are from the developing world.
HSBC says New Zealand's population growth, and investment in education, tools and technology will help propel the country to stronger growth.
It says other developed countries are handicapped by rising debt, a falling taxpayer base and weak demographics.
The report also places China as the world's biggest economy by 2050, pushing the United States into second position.