At least 185 laptops were stolen from the offices of the Limpopo Department of Agriculture, Land Reform and Rural Development in Polokwane.
Police spokesperson Colonel Moatshe Ngoepe said four armed men had accosted security guards on duty early on Tuesday.
"The suspects allegedly tied them up and locked them in one of the rooms, before proceeding to the offices of the director. Using trolleys, the suspects allegedly loaded 185 laptops valued at over R4 million from the office and later fled from the scene using a dark Toyota bakkie. No shots were fired."
In a statement, Agriculture and Land Reform Minister Thoko Didiza said she was "appalled at the thuggery".
"The incident has been reported to the law enforcement agencies, who are working tirelessly to bring the perpetrators to book," her department said.
A case of robbery was being investigated.