WorkSafe Western Australia will conduct an investigation into the death of a 38-year-old labourer near Harvey, last week.
According to WorkSafe, the man died after being thrown from an all-terrain vehicle on a farm in Benger.
Inspectors will also look into the death of a 55-year-old truck driver at Emu Flatts, near Kalgoorlie, on Saturday.
Investigators confirmed that the water truck the man was driving rolled on a dirt road.
WorkSafe WA Commissioner Darren Kavanagh said they would investigate whether or not both incidents were work-related.
Mr Kavanagh relayed his sincere condolences to the families of the victims.