New Zealand vs New Zealand Islands

New Zealand and New Zealand Islands both are nouns.

Word	Noun	Adjective	Verb	Adverb
New Zealand	Yes	No	No	No
New Zealand Islands	Yes	No	No	No

As nouns, New Zealand and New Zealand Islands are synonyms defined as:

New Zealand and New Zealand Islands: North Island and South Island and adjacent small islands in the South Pacific

New Zealand (noun)	New Zealand Islands (noun)
an independent country within the British Commonwealth; achieved independence from the United Kingdom in 1907; known for sheep and spectacular scenery	North Island and South Island and adjacent small islands in the South Pacific
North Island and South Island and adjacent small islands in the South Pacific