THE HAGUE (AFP) - Three people died on Wednesday after falling into a manure silo in the northern Netherlands and a survivor has been flown to hospital in a critical condition, police said.

"Three men have died in the workplace accident in Makkinga and one taken to hospital in a critical condition," police from the Friesland province tweeted.

Emergency services, including helicopters and rescue divers, scrambled to the farm after the men fell into the silo on Wednesday morning.

"Police are investigating how the accident happened. All four casualties worked at the business," police said.

Makkinga is surrounded by farmland around 50km south-east of provincial capital Leeuwarden.