Beacham Road is an undesignated speed zone area and has no signposts.
Murray-Wellington MLA Murray Cowper said many drivers were left angry, confused and asking questions after the multanova operator said they were in a 50km/h speed zone.
"After much investigation, I understand the City Of Mandurah requested a multanova camera to be placed on Beacham Street, in Mandurah, to assist in calming traffic along a 50 km/h stretch of road," Mr Cowper said.
"It appears that the deployment of a multanova camera to Beacham Road in Pinjarra may have been in error, as Beacham Road in the Murray Shire is an unsignposted rural road, where the default speed is 110km/h.
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"After much to-ing and fro-ing, between local governments, Main Roads and WA Police, I have received confirmation that no drivers will be issued with infringements if they were incorrectly detected speeding on Beacham Road on Monday, April 27," Mr Cowper said, having received a "flurry of complaints".
Murray Shire conducted a speed audit on Beacham Road and determined the appropriate speed limit is 90 km/h.