Health and Safety Authority Chief Executive Martin O'Halloran has said accidents on farms are foreseeable and preventable.
His comments come after two children died in accidents on farms since Friday.
A five-year-old boy died in an accident in Kincora near Ferbane in Co Offaly yesterday afternoon.
He has been named as Liam Lyons, of Raheenglass, Rath in Birr.
On Friday, a three-year-old boy died in an accident on his family's farm near Drimoleague in west Cork.
Speaking on RTÉ's Morning Ireland, Mr O'Halloran expressed his condolences to the 17 farming families who had lost relatives in farm accidents this year.
He said one of the challenges in ensuring farm safety is that farms are also family homes.
Mr O'Halloran said machinery was the biggest factor in farm accidents this year.
He said there was no logic in allowing children anywhere near farm machinery unless there is absolute total supervision.
He said that children and machinery must not go together.
"One of the challenges here is that it is also the home, the family home," Mr O'Halloran said.
"Wherever there is machinery, we would say there is absolutely no logic whatsoever to allow children anywhere near that, unless there is absolute, total supervision, because things can happen uncontrollably in a matter of a flash.
"So we would say children and machinery must not go together," he added.