Can I watch Demand 5 on Nintendo Wii and Wii U?

No, unfortunately Demand 5 isn't available on the Nintendo Wii or Wii U consoles.

On the Wii, there is no dedicated Channel for Demand 5. Content can't be viewed through because Opera web browser doesn't use the correct version of Adobe Flash Player.

On the Wii U, content can't be viewed through because Adobe Flash Player isn't supported.