The two sides agreed on the bulk of a free-trade agreement in April and have motioned they want to conclude a G-7 summit this month. The problem lies in the amount of access given to Australian farmers.
'There's a balance to be struck between your commercial interests and your desire to open up new markets,' said Conservative MP George Eustice.
'In any discussion on any part of government policy, there will be issues where different government departments have a shared interest and we have a discussion to establish a consensus,' he said.
A deal between the two is expected to boost Britain's GDP 0.02 per cent over 15 years.
Said the Department for International Trade: 'Any deal we sign with Australia will include protections for the agriculture industry and will not undercut UK farmers or compromise our high standards,' said the Department for International Trade.