Why doesn't New Zealand have snakes?

It is really something uncommon that a country could exist without a specie of snake in it. That's exactly the case with New Zealand. The only set of snakes you can see are the ones kept in the zoo. There have been so many explanation about why New Zealand doesn't have a single snake on her land.

This reason for the non-existence of snakes in New Zealand is simply her geographical location. The country surrounded by water, and more of being isolated from the rest of the world. It will take thousands of kilometers before you can spot the nearest landmass.

Another reason is the conscious effort of the New Zealand government to ensure they have a country totally free from snake but snakes do slip into their country via shipping containers and more reason for their is that the appearance of snakes in the country would endanger other native wildlife in the country