There are two Tiers of the Parent Category;
Tier one: this is the priority category, takes approximately six months to have the EOI selected and then approximately a further six months to have the application processed.
Tier two: this is the third priority for processing, after Parent Category applications under the old rules (before May 2012). It is estimated that applications under this category will take up to seven years, but in reality it may be even longer.
The difference between both categories can be found in the other requirements. To qualify for Tier One you must have either enough settlement funds or income or have a sponsoring child who earns at least the minimum income threshold.
To qualify for a visa under the Parent Retirement Category you must meet much of the same requirements as for the Parent Category. You may not have any dependent children and have at least one adult child who lives legally and permanently in New Zealand. You also need to bring funds or assets of at least NZ$1 million and invest them in New Zealand for at least four years. In addition you also need settlement funds of at least NZ$ 500,000 and have a substantial annual income. You also need to meet the health and character requirements.