Mr Key signed the agreement yesterday in the Turkish capital Ankara with his Turkish counterpart, Prime Minister Recep Tayyip Erdogan.
The two prime ministers also signed an Avoidance of Double Taxation Agreement and issued a joint declaration which outlines how ties between New Zealand and Turkey can be broadened and strengthened.
Historical ties could grow trade and investment between the two countries, Mr Key said.
"Turkey can become a key gateway to Europe, the Caucasus and the Middle East for New Zealand businesses. It also has a significant and rapidly expanding market of its own.
"New Zealand can play a similar role for Turkish businesses wishing to benefit from the fast-growing Asia Pacific market."
Today Mr Key heads to the Gallipoli peninsula where he will attend a number of commemoration services.
