The group of eight players including some nursing knocks like Dan Lydiate, James Hook, Shane Williams and Huw Bennett, took a minibus trip to Taranaki Base Hospital in New Plymouth.
They spent more than half an hour with youngsters in the childrens' unit before visiting other adult wards at the hospital.
Childrens' Ward Staff Nurse, Suzie Price, who is originally from Llanelli, said: "The players were great and the children all thought it was marvellous. They are all in patients here at the hospital but they have been following the Rugby World Cup on television so they recognised many of the players.
"The players have left these children with a very special memory indeed and all of us here really appreciate what they have done today.
"They signed autographs and chatted with the youngsters to make the children feel really important and special. We are all very grateful."
The staff nurse has lived in New Zealand for 14 years but her dad still sings in the Llanelli Male Voice Choir.
Wales centre Jamie Roberts, who is a medical student as well as a professional rugby player, said:"It was great to meet the children and all of the players involved really enjoyed the experience.
"It was our privilege to spend some time with them because seeing how happy and determined they are is very humbling.
"We could spend all our time training or studying the match videos but there is always a moment we can utilise in a way which helps some others
"The staff at the hospital were really welcoming and they made us know how much they appreciated us spending some time with them."