A Heiltsuk news release says about 50 members put the office on lockdown around 5:30 p.m. Sunday.
"Occupying the inside of the building and setting up tents outside on the lawn, the delegation of elected leaders, hereditary chiefs, women, and children is refusing to leave the grounds or to let anyone into the office until the Nation’s demands are met," the band said Sunday in a statement.
The First Nation is fighting what it believes to be an unsustainable commercial herring gillnet fishery in its territory, based on its own estimate of stock numbers.
The Heiltsuk met with federal officials over the issue last week and again Sunday afternoon, but failed to reach an agreement. Band official Kelly Brown says the industry took 680 tons out of the same area with a recent seine fishery and that a gillnet fishery "would only add insult to injury."
The Department of Fisheries and Oceans opened the herring-roe seine fishery near Bella Bella a week ago, saying there is enough stock to support the harvest.
The band says opening the fishery despite its opposition violates its constitutional rights.
Chief Councillor Marilyn Slett says she feels they have exhausted all means of negotiation with Fisheries and Oceans and the Heiltsuk are prepared to protect the herring by any means.