Justin Timberlake has been slammed by a charity organisation that claim he hasn't been involved enough in their activities.

The singer and actor teamed up with Shriners Hospitals for Children five years ago to put on a celebrity golf event in Las Vegas to raise funds for the charity.

The organisation help run a number of children's hospitals that take in patients regardless of their parents' ability to fund the fees.

Tournament chairman Raoul Frevel said that he is disappointed how much time Timberlake has spent with the charity since the golf day. He said:

"We're a world-class organisation. At the time we got involved with golf, we were told by the [Las Vegas PGA] Tour we needed a big name, and that's how our relationship with Justin came about. Justin's a wonderful person. But we tried everything we could to get him more involved with our kids and the hospitals. But it seemed that when the TV cameras weren't on, he disappeared."

However, Frevel praised the popular singer for adding "star power" to the event and golf in Las Vegas. He said:

"The future of pro golf here in Las Vegas wasn't very secure when Justin and the Shriners came in five years ago. Justin added a level of cache and star power in a city that understands the value of that."