Mr Hubbard was killed last month in a car crash near Oamaru.
The Hubbard Investors and Supporters group wrote to Ms Collins and Mr Finlayson this week, asking for Mr Feeley to be dismissed immediately.
"That Feeley deliberately chose this book to give out as investigators' 'booby prizes' shows a complete lack of professional conduct, which is even more appalling and disgraceful that it occurred while the SFO was still in the middle of conducting a serious fraud investigation into the affairs of Allan Hubbard," said the letter, also sent to the Herald.
"Feeley's conduct ... shows he held a deep-seated attitude and underlying contempt towards Allan Hubbard.
"We believe the investigation by the SFO into the affairs of Allan Hubbard was biased and tainted from the beginning, and Feeley's actions at the SFO Xmas party further confirm this.
"Adam Feeley has showed a complete lack of integrity for the position that he holds, and we hereby believe after the 'booby prize' incident, and also his recent conduct with the Bridgecorp wine affair, he is no longer fit to hold any position within the SFO if it is to maintain any credibility in the future.
"It is our belief that Feeley should be dismissed for improper conduct immediately."
Mr Feeley is also facing an employment investigation that he celebrated criminal charges being laid against Bridgecorp chief Rod Petricevic by serving staff a bottle of champagne belonging to that firm's directors.
Ms Collins referred the matter to the State Services Commissioner, Iain Rennie, Mr Feeley's employer, after the Herald revealed the incident.