A spokeswoman for the Hubbard Support Team, Jan McPherson, said giving the books away as joke prizes seemed to be mocking Mr Hubbard and showed poor judgment during an open investigation.
" He [Mr Feeley] is meant to be above that sort of behaviour, in the position he holds."
The SFO's general manager of corporate services, Victoria Currey, said Mr Feeley was travelling and unavailable to comment.
"I can confirm that, like many organisations, the SFO holds staff functions at festive times of the year and when milestones are achieved in our work."
She said Mr Hubbard gave a staff member a copy of his book at the end of an interview.
It had been treated the same way as any gift to the office, and was given to the staff raffle.
"As the State Services Commission is looking at matters raised by the New Zealand Herald last week, the Serious Fraud Office is not in a position to comment on any other matters relating to the office at this time," Ms Currey said.
Mr Feeley is facing an employment investigation for celebrating criminal charges against Bridgecorp chief Rod Petricevic by serving staff a bottle of champagne belonging to that company's directors.
SFO Minister Judith Collins referred the matter to the State Services Commissioner, Iain Rennie, Mr Feeley's employer, after the Weekend Herald revealed it last week.
Pressure has mounted on Mr Feeley this week and yesterday, a top Auckland criminal lawyer called for his resignation over the champagne incident.
"He's in a position of responsibility and I think he's shown absolutely poor judgment," said Criminal Bar Association president Tony Bouchier.
"They had a celebratory drink - that on its own is not so bad, but the SFO really have got to be seen to be absolutely unbiased."
- Additional reporting: APNZ
