William and Kate depart New Zealand for Australia

Britain's Prince William and his wife Kate departed New Zealand with their baby son Prince George on Wednesday, an AFP reporter saw, heading for Sydney to begin the Australian leg of their tour Down Under.

The royals waved as they boarded an Australian air force 737, with William carrying his eight-month old son in his arms.

On their final day in New Zealand, William and Kate were introduced to German Shepherd puppies destined to become police dogs when they visited Wellington's Royal New Zealand Police College.

They also conducted a walkabout in the capital's downtown area.

The have been treated like celebrities during their ten-day visit to the former British colony, attracting crowds in the tens of thousands, even in small regional towns such as Blenheim and Cambridge.

The New Zealand trip has included yacht racing, Maori ceremonies involving warriors with tattooed backsides on display, and an adrenaline-charged jetboat ride on a lake nestled between the picturesque mountains of Queenstown.

The highlight was undoubtedly a "play date" involving George and 10 local babies at Wellington's Government House, giving the public a rare glimpse of the royal toddler.

They set off from Wellington at 0100 GMT and are due to touch down at about 0430 GMT.

They will travel straight to the Sydney Opera House for an official reception to begin their Australian tour, which continues until April 25 and includes a trip to Uluru (Ayers Rock) in the country's fabled red centre.