Jacinda Ardern's personal touch among New Zealand gifts for royal baby

Prince William and Kate leave hospital after the birth of their third child.

Prime Minister Jacinda Ardern says a baby garment made by her sister-in-law will be included in gifts sent from New Zealand to the new royal baby.

The Duke and Duchess of Cambridge showed off their newborn son to the world on the steps of the Lindo Wing this morning.

Proud parents William and Kate held the baby prince - their third child - as hundreds of cameras clicked and flashed in front of the private maternity unit in Paddington, London.

The duchess gave birth to the 8lb 7oz (3.8kg baby boy at 11.01am on patriotic St George's Day after being admitted before 6am on Monday (UK).

During his first photocall, the baby, a brother to Prince George and Princess Charlotte, was wrapped in a white lace shawl and a matching hat. Only just under 7 hours old, he was carried in his mother's arms.

Ardern, who herself is pregnant, told Newstalk ZB's Mike Hosking that Kiwiana and homemade clothes are in the basket of gifts for the baby.

The country will also be giving the unnamed child a range of children's books.

"Hairy Maclary is already a royal family favourite which is lovely, got a blanket made from New Zealand wool and I've chucked in a personal gift, which is a little romper my sister-in-law made that's got a Buzzy Bee lining in it."

Ardern said it was incredible Kate appeared so quickly in public.

"I just think we should all just let her have a cup of tea and go back to bed," she said TVNZ's Breakfast.

New Zealand waited until the baby was born before talking about what presents were being sent.

Smiling broadly, Kate, who was dressed in a vibrant red Jenny Packham dress with a white lace collar, adjusted the baby's shawl in windy conditions outside the hospital.

Minutes after the brief photocall, the couple headed home to the sanctuary of Kensington Palace.

- NZN, staff reporter