The Cornish-based group had been due to perform at the G Live venue in Guildford, Surrey, shortly after 11.45am yesterday, but the gig was called off following the incident.
Police were called to the scene after a report that two men were trapped under a metal door. One of the men suffered serious injuries to his legs, officers confirmed.
He was treated by paramedics but was declared dead at the scene. The other man - an unnamed member of the ten-strong group - was taken by ambulance to St George's Hospital, Tooting, with serious head injuries.
A spokesman for the band said: "Tragically, a member of the Fisherman's Friends touring party died yesterday following an accident at the G Live venue in Guildford where the group were due to perform.
"One of the Fisherman's Friends was also seriously injured in the accident and remains in hospital."
In a statement Darcus Beese, president of Island Records, the group's label, said: "Everyone here is shocked by this tragic event, our hopes and prayers go out to the friends and families of those involved."
Tributes were paid this afternoon to the Fisherman's Friends tour manager, who was named as the man who died hours before the group were due to perform.
Another man, Trevor Grills, a member of the Cornish-based ten-piece, remains in hospital tonight with serious injuries after being caught up in the incident before their scheduled gig in Surrey yesterday.
Paul McMullen, the band's manager, was pronounced dead at the scene - the G Live venue in Guildford - following the incident at 11.45am. His death - and Mr Grills' condition - was confirmed by a Fisherman's Friends spokesman.
A spokesman for the group Said The Maiden, who had worked with the singers, said: "We are deeply saddened by the news of the accident in Guildford yesterday. Paul was an amazing man, who gave us a fabulous opportunity to sing for the Fisherman's Friends.
"We feel honoured and grateful to have been able to work with him. Our thoughts and prayers are with his family and the guys tonight."
The Health and Safety Executive has been informed of the death.