Waste disposal company Transpacific Industries has downgraded its full year profit and earnings forecasts on lower garbage volumes in its Cleanaway business.

Transpacific said lower volumes were also being exacerbated by Queensland customers deferring the removal of waste to landfill until that state's landfill levy is removed on July 1.

It said on Monday it expects net profit for the year to June 30 to be between $8 million and $13 million, down from its previous guidance of $17.3 million.

Underlying earnings for the full year would be between $435 million to $442 million, down from the previous guidance of $445 million to $459 million.