"Given what's come out I think everyone is now curious, so I would like if, and I do stress the word if, if there is more to all of this than meets the eye then it would be good for the truth to come out," he said.
Read more: John Armstrong - Crisis calls on Key to use all his skills
Key: National campaign still on track
Former Justice Minister Ms Collins resigned from the Cabinet on Saturday. Her departure came after an email was revealed in which her name was linked to a smear campaign against Mr Feeley run by Whale Oil blogger Cameron Slater and other parties linked to former Hanover director Mark Hotchin.
Mr Hotchin was at the time under investigation by the SFO.
At the time Ms Collins had responsibility for the SFO and in the email Slater claimed she had been "gunning" for Mr Feeley.
Ms Collins has strongly denied any wrongdoing and asked for an inquiry but resigned her ministerial posts. The Prime Minister is expected to announce details of the inquiry tomorrow or on Wednesday.
Watch: Dirty politics: PM's office receives subpoena
Asked yesterday whether he was ever concerned that information he had given to Ms Collins or her officials might have found its way to Mr Hotchin or Hanover's lawyers, Mr Feeley refused to comment directly on the case but confirmed he did "periodically give ministers indications of where particular investigations were going".
About 16,000 people with investments totalling more than $500 million lost most of their money following the failure of Hanover and related companies, and the sale of assets to Allied Farmers.
The SFO did not lay charges but the Financial Markets Authority brought civil charges that will be heard in court next year.
Read more of the Herald's coverage:
• Calls for a full commission of inquiry
• The money men and how they toppled Collins
• Commissioner concerned by allegations
• Gallery: Collins in cartoons
• I'm the victim of a smear campaign: Judith Collins resigns
• Resignation reaction: 'Too little, too late'
• The email that brought down Judith Collins
• Collins resigns: Blogger backs mate
• Collins resigns: Jared Savage and Fran O'Sullivan respond
This morning Mr Feeley assured Hanover investors that any decision not to prosecute would not have been influenced by a Government minister.
"In my entire time at SFO I never made a decision to investigate or not to investigate, prosecute or not to prosecute, based on whether it would be popular with the public, with investors, or indeed the government of the day," Mr Feeley told RadioLive.
"The public should feel comfortable that certainly I, and I have no doubt [current chief executive Julie Read] operates no differently to me, we took our decisions always independently, and I think one of the trademarks of the SFO is it's always been fiercely independent.
"We never made a decision to investigate or not investigate, or to charge or not charge, some body or some organisation based on media pressure, based on popular opinion, based on what bloggers were saying."
Meanwhile the Financial Markets Authority's former boss Sean Hughes, today said he did not seek a second term in the role, partly because of the attacks he was subjected to on right-wing blogs Whale Oil and Cactus Kate.
Mr Hughes told Radio New Zealand the blog attacks were an attempt to "put us off our game".
"They were distasteful, they created an unnecessary distraction and anxiety for the organisation and the team that I was leading, and of course the personal attack on me was just unnecessary.
"It was not fair on my family, or myself, to put myself through an ongoing experience such as this."
A police spokesman said they were not yet considering an investigation, but would monitor the Government-led inquiry to see if anything of interest came to light.
"At this time police have not received any complaints in relation to the resignation of Judith Collins at the weekend," a police spokesman said in a statement.
"Police are aware that the terms of reference of an inquiry into these matters will be announced later this week.
"Police will monitor the progress of any relevant inquiry for matters which may become of interest from a police perspective."
However, officers would assess any allegation of a criminal nature they are made aware of, the spokesman said, but these are dealt with on a "case-by-case basis".
"Police will not be drawn into issues of a political nature which do not involve substantiated issues of alleged criminality."
To complaints have been laid in relation to Nicky Hager's Dirty Politics book, the spokesman said, one by blogger Cameron Slater, whose hacked emails were used in the book, and one from the Green Party. They are still being assessed, he said.
