State general manager Nial Stock said proceedings for the proposal were before the State Administrative Tribunal for further consideration.
�The JDAP decision is disappointing as SITA remains confident the landfill is a safe, suitable and appropriate development for the proposed site,� Mr Stock said.
The JDAP first considered the project in April last year but held another review of the proposal following discussions before the SAT.
Mr Stock said a new works program submitted to the Department of Environment Regulation (DER) included significant reductions in the landfill footprint and total volume of waste.
�We also re-forecast the `life of the facility from approximately 37 to about 20 years,� he said.
The Shire of York has repeatedly refused the landfill proposal, strongly opposed by the Avon Valley Ratepayers Association.
Protesters urge the community to �Stop 40 Years of Perth Rubbish in York� – their Facebook title – and to raise the environmental concerns.
They say the latest JDAP narrowly upheld the original decision in a three-two vote not to allow the landfill site because of planning issues.
�This decision (proposal) should be appealed by all members of the public for environmental reasons,� say the protesters.
A Department of Environmental Regulations (DER) officer present at the meeting stated the DER had approved the revised landfill proposal.