Prince William left New Zealand shores yesterday morning, protesting that he did not want to go and had high hopes of being able to return for next year's Rugby World Cup.

The prince's reluctance to leave delayed the Royal NZ Air Force plane that took him to Australia by 30 minutes after he lingered at Wellington Children's Hospital.

Emerging from the final engagement of his two-day visit, he saw about 100 people waiting outside and squeezed in one last chance for a "walkabout", apologising profusely for having to make it so quick.

He told waiting reporters he hoped to return for the Rugby World Cup.

Prime Minister John Key has invited Prince William and Prince Harry to the tournament.

He said his time in New Zealand was "fantastic".

"Very welcoming, very warm, very fun and I wish I wasn't going."

It was his first official foray into royal duties and seen by many as the start of his apprenticeship to become king.

His lengthy walkabouts and ability to put children at ease prompted comparisons with his mother, Princess Diana.

"It's important for humanity that everyone realises we are all the same. I really enjoy it. I get a buzz out of it and seeing kids smile when they are ill. It means a lot to me."

However, he was circumspect when asked if he had learned his own winning ways from his mother, saying he was nowhere near the same level.

"She had a fantastic affinity with kids and with everyone. I just go and meet people and enjoy their company. I like meeting people, so it helps."

In the hospital, heart patient Ethan Fagaloafa-Time, 12, said he had thought the prince would be "a bit up himself".

But he came away a fan after talking rugby with the prince, saying his accent was "pretty funny" and a little bit "posh" but he was a good guy.

Outside, Oliver Craig, 10, and his two younger siblings Sophie and Reuben were also impressed after a brief encounter.

"He can handle things quite well," Oliver observed.

While Prince William has been the headline act, for Mr Key the prince's visit has meant two days of playing second fiddle.

He was barely noticed by many and had to put up with photographers and the public calling to him to move aside to give them a clear view of the Prince.

He took such treatment in good humour, saying he had no problems with such lowly status while in the presence of royalty.

He believed the trip "was a chance for New Zealanders to experience at first hand a fine young man".

He also hoped the prince would be able to return to the country next year, if his schedule allowed.

The prince travelled to Sydney yesterday for a two-day visit - his first to Australia since he was a baby.

He will return to Britain on Friday.