Turnbull pledges support for petrol tax cut plan …… 

The Opposition's Treasury spokesman, Malcolm Turnbull, has been forced to publicly declare his support for the Coalition's policy to cut petrol tax, after a damaging email leak.

It has been revealed Mr Turnbull argued against the 5 cent excise cut before it was announced in Opposition Leader Brendan Nelson's Budget reply speech. 

Mr Turnbull emailed Dr Nelson's office saying the policy was a bad idea. 

He has denied leaking the email, but has refused to comment on its content. 

'We all support the policy,' he said.