Merri Harris, Christine Randall and Michael Ricketts recently resigned from the shire.
Ms Harris and Mr Ricketts told Comment News they resigned over concerns about the shire’s leadership and decision-making.
All three represented the north ward.
The six men left on council include Barry Urban and John Kirkpatrick.
Mr Urban and Mr Kirkpatrick threatened to resign on March 11, along with Mr Ricketts. However, after a meeting, the trio resolved not to resign. But Mr Ricketts changed his mind by Tuesday morning after the ordinary council meeting.
Shire president Bruce Moore said the shire had consulted with the WA Electoral Commission and the Department of Local Government and has approval for the positions to remain vacant until the October 2013 election.
‘Serpentine-Jarrahdale Shire believes a council of six is adequate to lead the shire through to the October 2013 election,’ Cr Moore said.