Norwich have banned the two supporters who confronted former manager Bryan Gunn during the opening day defeat to Colchester from Carrow Road.
Two men ran onto the pitch during the first half of the 7-1 thrashing last month and had to be physically restrained by kit manager Manny Fowler.
"We will not tolerate any behaviour which compromises the safety of our staff or supporters," said chief executive David McNally.
"As a result of this incident we were forced to pay for an independent safety inquiry and our policing bills have increased
"In real terms this incident alone cost Norwich City football club a five-figure sum.
"The recommendation of the inquiry was an indefinite ban for the supporters involved and that has now been put into place."
Copyright (c) PA Sport 2009, All Rights Reserved.