Tony Abbott's claim that bureaucratic red tape could prevent him from cutting the salary of a staff member whose ''booze-fuelled brain snap'' at a cocktail party made national headlines has been thrown into doubt.

Under guidelines that dictate pay rates for parliamentary staff, it is possible for the Opposition Leader to reduce the salary of Mark Roberts, a legal academic told Fairfax Media.

But Dr Roberts would have to take a pay hit of up to $58,000.

Dr Roberts was removed as Mr Abbott's senior policy adviser on Friday after details emerged of his unsavoury outburst directed at the head of an indigenous education charity.

Dr Roberts has admitted threatening Andrew Penfold, chief executive of the Australian Indigenous Education Foundation, that a Coalition government would cut funding to his organisation.