A coin dealer will almost certainly have a collection of New Zealand coins.
Alternatively, you could try a currency exchange office.
The thickness of a two dollar coin is 2.70mm thick.
The highest denomination New Zealand coin in general circulation is the Two Dollar coin. The highest denomination coins minted for the Reserve Bank of New Zealand are the 1990 gold $150 coin, and the 1998 platinum $150 coin.
New Zealand issued paper One Dollar notes in two different designs. The first from 1967 to 1981 and the second from 1981 to 1991 when they were replaced by a coin.
The size of the coins in relation to each other. The Australian One Dollar coin at 25 mm is significantly larger than the Australian Two Dollar coin at 20.62 mm. By comparison, the New Zealand One Dollar coin at 23 mm is smaller than the New Zealand Two Dollar coin at 26.5 mm.
From 1967 to 1989, the Kiwi was featured on the reverse of the New Zealand 20 cent coin. In 1990, a commemorative 20 cent coin was issued featuring the ship HMS Tory. From 1990 to present, a Hei Tiki Maori carving is featured on the reverse of the New Zealand 20 cent coin.
The 'Rifleman', NZ's smallest bird, was pictured on the NZ$2 note but this note was removed from circulation in 1991 and replaced with a $2 coin. The bird depicted on the $2 coin is the Kotuku (White Heron).
The highest denomination of New Zealand banknote is currently the One Hundred Dollar note. The Reserve Bank of New Zealand has no plans to introduce a Two Hundred Dollar banknote in the foreseeable future.
There were two variants of the New Zealand Two Dollar note. A New Zealand Two Dollar note (Issue 3 [1967 - 1981] - Queen facing to the left)(depending on the Chief Cashier and serial number), uncirculated and in absolute mint condition could fetch anything from $35 to $100 NZD. If it has been circulated but still in good condition, it might fetch anything from $6 to $30 NZD. A New Zealand Two Dollar note (Issue 4 [1981 - 1991] - Queen facing forward)(depending on the Chief Cashier and serial number), uncirculated and in absolute mint condition could fetch anything up to $15 NZD. If it has been circulated but still in good condition, it might fetch anything from $5 to $7 NZD. New Zealand Two Dollar notes were last issued in 1991. A Two Dollar coin replaced them. A reputable coin dealer will be able to give a more accurate valuation.
If the coin is a 2007 coin - A New Zealand 2007 bronze finish 10 cent coin (Tuatara Commemorative), uncirculated and in absolute mint condition could fetch up to $10 NZD. There were 15,000 minted. A reputable coin dealer will be able to give a more accurate valuation.
The smallest mintage of New Zealand predecimal general circulation coins was the 1961 Halfcrown with only 80,000 minted. The smallest mintage of New Zealand decimal general circulation coins was the 1997 Two Dollar coin with only 1,008,000 minted.
A New Zealand 2005 Two Dollar coin, uncirculated and in absolute mint condition could fetch up to $5 NZD. There were 5 million minted. A reputable coin dealer will be able to give a more accurate valuation. These coins are still potentially in circulation so, unless they are part of a Proof or uncirculated mint set or are individual Proof or uncirculated coins and in absolute mint condition, they are worth Two Dollars.
New Zealand withdrew its two cent coins from circulation in 1990; the smallest denomination coin in NZ is now the ten cent coin.