William appeared to suggest he and wife Kate are already planning a another child when he encouraged a well-wisher to make a second baby gift after giving them one for their son.
After Cynthia Read presented them with a lace shawl she had made for George on behalf of the New Zealand government, William told her: "You might have to make another one soon."
Mrs Read, who emigrated from Newcastle with her Scottish husband Ken, a geologist, eight years ago, added: "The way William said it was like he was dropping a hint, letting me in on a secret."
Asked if she thought he meant a brother or sister for eight-month-old George would soon be on the way, she replied: "Maybe. I couldn't possibly comment. Obviously if I'm asked to do another one I would be honoured, but we'll wait and see."
William and Kate met Mrs Read in the town of Cambridge in the Waipa district on the North Island of New Zealand where the royal couple wowed crowds of 15,000 when they went on a walkabout after paying their respects to First World War heroes. In a poignant gesture the royal couple left a single red rose each at a war memorial in the aptly named town.
But Kate later confessed to one well-wisher that her green Erdem coat was apparently a "bit bright" for William.
Mrs Read, 61, was commissioned by New Zealand's government to knit the lace shawl after spinning it from merino wool.
She said: "It took me four months and I would have liked longer."
An award-winning member of the Creative Fibre circle, she told William that the Filmy Fern pattern white shawl, with intermingled fern leaves, was designed by Margaret Stove, who also made one for William when he was a baby.
Mrs Read said: "He didn't know that. Margaret, who must be in her 70s, designed this one but I made it.
"Kate told me they were really happy with it and George wore it a lot.
"She said it was so lovely and soft. They have brought it to New Zealand and he is wearing it, but she apologised for not so far finding an appropriate event outdoors to wrap him in it.
"I shouldn't thInk he will wear it much more as he is nearly a little boy.
"It was wonderful to meet them, they were a charming couple."
A sibling may soon be on the cards for George but during the day he passed one of his childhood milestones when the future king received his first bike.
William and Kate were presented with the tiny cycle for their baby son, a minuscule crash helmet and a sleek racing top emblazoned with his name on the back.
It will be a while before the baby Prince will be taking his first ride but his proud parents could not contain their delight when they received the presents as they opened New Zealand's national velodrome in Cambidge.
George is now the proud owner of an Avanti Lil Ripper bike for children aged two and older, which features a bespoke design by Shane Hansen, one of New Zealand's leading contemporary artists.
John Struthers, 76, founder of the bike firm Avanti, made the presentation and said about the royal couple: "They are very very thrilled, he was really appreciative of it. It gives two year olds independence and freedom to take their first big step in life.
"She was looking forward to the time when George will be able to ride it." And he joked: "I hope they don't get excess baggage (charges) you know what airlines are like."
George's list of presents is growing by the day and his bike will be added to the miniature version of Sealegs, an amphibious boat, his parents received yesterday when they went sailing in Auckland.
The Duke gave a short speech before he launched the velodrome with his wife and told spectators sitting in the stands: "It is a great honour for Catherine and me to be here to pay tribute to New Zealand's cycling heritage and its cycling future.
"I know what a special place cycling holds for New Zealanders and what a beneficial and thrilling sport it is. The Avantidrome represents cycling's pinnacle and will no doubt be the crucible for many of tomorrow's winners."
William and Kate both started exhibition races - with the Duke pulling a face when he fired a pistol to set opposing groups of three riders on their way in the team pursuit.
Earlier in the day while in the town of Hamilton the royal couple carried out solo engagements for the first time during their tour of New Zealand and Australia. William visited the company Pacific Aerospace to learn about an innovative aircraft the firm makes and he revealed he still indulges his passion for flying - despite leaving the RAF - but has not had as much time in the air as he would like.
And he could not resist chatting about George, saying his son had settled into a routine and was keeping them busy.
Damian Camp, chief executive of the aviation firm, said about his conversation with the Duke: "He said he still does some flying - all helicopter based - but not as much as he wants to."
He added: "He said George has settled into a nice routine but were keeping Mum and Dad on their toes but they're all enjoying their stay."
The Duchess' engagement took her to the nearby Rainbow Place children's hospice where she sympathised with one little girl coming to terms with her mother's terminal cancer.
Kate, who is patron of the East Anglia's Children's Hospice, sat at a tiny table with six-year-old Bailey Rupe and enjoyed the very British ritual.
Bailey said afterwards: "I was excited to meet a real princess and it made me feel like a princess for the day too."