As a lawyer you can either hold a practising certificate as a barrister (in which case you are subject to the various rules governing barristers' conduct) or you may hold a practising certificate as a barrister and solicitor (in which case you are subject to all the rules governing barristers and solicitors).
A barrister ... works mainly in the Courts and Tribunals. Their work includes presenting evidence, making submissions on behalf of their clients, representing parties in criminal trials, handling domestic disputes in Family Courts, dealing with civil claims for damages and compensation.
A solicitor ... may be involved in general advisory work, property transactions, estates, arranging finance and commercial work. They may also be involved in drafting wills, administering estates, advising on tax, forming companies, making contracts and raising or securing loans.
Please contact New Zealand Law Society for information on the requirements for becoming a lawyer.