The airline has also secured options over eight further production slots, Air New Zealand strategic development general manager Nathan Agnew said.
"These new aircraft will provide Air New Zealand with a solid platform to realize its growth ambitions over the next decade," Agnew said.
"Given their capability to fly direct (from New Zealand) to regions like South Africa, India, South America, Asia and deep into China and North America, we will have some exciting new opportunities to pursue."
The airline has said it plans to launch at least one new international route every year.
The first Boeing 787-9 is due to start service in 2011 and the last of the eight aircraft is scheduled for delivery in 2013. The Dreamliner would use 20 pct less fuel compared with similar aircraft flying currently, Agnew said.
The Boeing 787-9 is capable of carrying 250 to 290 passengers and has a range of up to 16,300 kilometres (10,130 miles).
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