A good book keeper will keep records of all your day today to transactions so for each day or week you know how many sales and purchases your business has made and how much they are for.
A good book keeper can do it all. They will be registered tax agents and have a detailed knowledge on New Zealand tax. This means they can offer you all the same tax services as an accountant normally at a fraction of the price.
There are only two reasons you have a book keeper or tax agent do your books.