An online debate between Malcolm Turnbull and Stephen Conroy on broadband policy has descended into sledging and personal attacks.

The Coalition's communications spokesman, Mr Turnbull, mocked Senator Conroy's deal-making, saying the Communications Minister had bungled his $12 billion negotiations to decommission Telstra's copper telephone lines.

Senator Conroy replied by asking Mr Turnbull what advice he gave to former HIH Insurance boss Ray Williams, who was jailed after overseeing what was Australia's biggest corporate collapse. Mr Turnbull was named in a $500 million damages claim brought by the liquidator of HIH in 2003 (which was ultimately settled in his favour).

"You are so desperate that all you can do is smear," Mr Turnbull said in the debate, hosted by website OurSay.