Freedom of Information requests by union Unite show that in 2015/16 there were 9,219 inspections and this reduced to 7,912 in 2016/17.
The union is now seeking urgent meetings with ministers and the Health and Safety Executive as the safety body faces major funding cuts.
Unite assistant general secretary Gail Cartmail, said: “These figures are alarming as they demonstrate a huge decrease in vital lifesaving inspections.
“Sadly there remain far too many employers who are all too willing to cut safety regulations and it is only the genuine prospect of an unannounced inspection which keeps them in check.
“The government has slashed funding for the HSE and it is clear that it is increasingly struggling to make ends meet.”