Prince William took a break from his duties as a doting father to newborn son Prince George on Wednesday, attending an agricultural show on the Welsh island of Anglesey.

The new father, who has been serving a three-year posting as a search-and-rescue pilot at Royal Air Force Station Valley in Anglesey, Wales, told the audience that while his military duties were "demanding," looking after a three-week old baby wasn't any easier.

"I thought search-and-rescue duties over Snowdonia were physically and mentally demanding but looking after a three-week old baby is right up there," William joked with the audience.

Anglesey has been home to the Duke and Duchess of Cambridge since the university sweethearts married in 2011. Wednesday's event was William's first official engagement since the birth of his son on July 22.

William will be leaving his post at the RAF base in September. He is expected to cease being an active member of the armed forces.

William attended the event solo while his wife stayed behind with his son.

"(Kate) and George would have loved to have been here," William said. "(George) is pretty loud and extremely good looking," said the proud father.

While at the agricultural show, William took part in a royal inspection of prize winning cattle.

"It is really nice to see the younger generation," one woman at the show commented. "(Prince William) is so down to earth."

Before leaving, William addressed the crowd partly in Welsh, thanking the island's residents for their hospitality.

"This island has been our first home together, and it will always be an immensely special place for us both."