The Health and Safety Executive told the BBC the incident involved an excavator at a building near a farm at Llanrug, near Caernarfon.
North Wales Police have named the dead man as Dr Eilir Hedd Morgan, from the Blaenau Ffestiniog area.
Dr Morgan was a lecturer at Bangor University. It is not clear what he was doing working on a building site.
A post-mortem examination has been carried out and the coroner informed.
A police statement said: “A post mortem has been conducted and the circumstances of Mr Morgan’s death are still being investigated by NWP jointly with the HSE.
“There are no further details available at present.
“The family ask that their privacy be respected at this time.”