A school fundraiser in South Australia has exceeded expectations - thanks to the same sex marriage debate.

Craigburn Primary School students were encouraged to wear a dress or casual clothes to school - in a bid to raise money for impoverished girls in Africa.

However, Senator Cory Bernardi criticised the idea, calling it 'gender morphing'

Australian correspondent Murray Olds told Mike Hosking the comments caused immediate backlash.

"As soon as Cory Bernardi got a hold of this, he's a massive anti-same sex marriage campaigner, he's gone nuts. Well guess what the 900 bucks has become $50,000 and climbing."

LISTEN ABOVE AS MURRY OLDS SPEAKS WITH MIKE HOSKING