Use of the two buildings was forbidden and warning signs were put up to warn people to steer clear of the sites.
SWDC planning and environment group manager Murray Buchanan said in a report, tabled at Wednesday's council meeting, the owners had until April 20 to comply with the notice.
Mr Buchanan told the Times-Age neither owner had contacted council "to express disagreement".
"We can only presume at this point that they intend to comply."
He said council would be inspecting the sites after the deadline to check whether the buildings had been removed or demolished: "We can at that point, if the buildings are still there, arrange for their removal at the owners' cost."
Mr Buchanan said before such a step was taken, council would try to contact the owners to confirm their intentions.