Check out the integrity of the socket - plug something else in.
Check out the integrity of the fuse - swap it with another appliance.
If the socket and fuse remain good then there's an issue inside the machine - reach for your tool kit and electrical measurement meter - or call for a repair specialist.
Sometimes our electrical appliances have safety cut-out switches that turn things off if they get too hot - vacuum cleaners have them for instance and I wouldn't be surprised if tumble dryers don't have them as well - it might be a faulty over-heat switch - but I only guess.
There's a New Zealand contributor on here who's very knowledgeable about these things - he might have a more useful opinion.
Good luck...
W Mitty, October 2014
