Evidence deemed inadmissible at his trials could also be heard, University of Otago professor of criminal law Kevin Dawkins said yesterday.
Prof Dawkins was commenting on an announcement yesterday from Justice Minister Simon Power, who confirmed the onus was on Mr Bain's legal team to meet an "extraordinary circumstances" test in its bid for compensation.
Prof Dawkins said a compensation starting point for Mr Bain would be $100,000 for each year in custody - a minimum of $1.3 million.
But first Mr Bain's legal team needed to satisfy a third party, possibly a QC, Ministry of Justice officials or an overseas expert - of innocence on the balance of probabilities, and meeting the extraordinary circumstances test.
Under Cabinet guidelines adopted in 1998, claimants eligible for compensation are limited to those whose convictions had been quashed on appeal without order of retrial or who had received a free pardon, Mr Power said.
In 2007, the Privy Council quashed Mr Bain's conviction on the grounds of a substantial miscarriage of justice and ordered a retrial.
Last June, Mr Bain was found not guilty at the retrial.
While Mr Bain fell outside Cabinet's guidelines because he was acquitted following a retrial, the Crown had "residual discretion" to consider claims falling outside the guidelines in "extraordinary circumstances", Mr Power said.
Asked to clarify "extraordinary circumstances", the minister said they must include some feature that took the applicant's case outside the ordinary run of cases in which appeals had been allowed.
Examples of extraordinary circumstances would include, but not be limited to, irrefutable DNA evidence, strong alibi evidence, or serious wrongdoing by authorities, such as the planting of evidence.
"The test of `extraordinary circumstances' is, however, inherently an open-ended one.
Cases may have other extraordinary features that render it in the interests of justice that the compensation claim be considered, and it is up to a claimant to show the existence of such features."
Under residual discretion, Mr Bain would also need to establish innocence on the balance of probabilities.
Mr Power said officials were working with Mr Bain's lawyers to devise a process for assessing the compensation claim, and confirmed no deadline had been discussed.
In regards to a possible compensation payout, the minister said it was "too early in the process for that".
Prof Dawkins said the compensation bid differed from a criminal trial in that any evidence deemed inadmissible could be included - which could possibly include the 111 recording and an alleged alibi Mr Bain told a former school friend.
Mr Bain's legal team also ran the risk that a different conclusion to the retrial could be reached, citing the February 2009 Cabinet decision which declined Rex Haig's application for compensation for wrongful conviction and imprisonment.
Mr Haig was convicted in 1995 for the murder of fishing boat crewman Mark Roderique and spent 10 years in prison before his conviction was quashed by the Court of Appeal.
He then applied for compensation.
"Apart from the possibility of civil proceedings, the risk is the applicant [Mr Bain] might be re-convicted in the court of public opinion," Prof Dawkins said.
Bain advocate Joe Karam was unaware of the minister's statement until contacted by the ODT.
After reading the statement, he declined to comment, but said a meeting with Mr Bain's legal team would be held "very soon".
Mr Bain's lawyer, Michael Reed QC, did not return calls yesterday.
Last month, Mr Reed said Mr Bain was "penniless" and "we would not make the application if we did not think it was justified".
The head of the Bain support group, Catherine Spencer, of Dunedin, said she preferred not to comment on legal issues and declined to estimate the amount of compensation Mr Bain should receive.
"The 15 years he spent in jail, the family he lost ... the people nearest and dearest to him - nothing is going to compensate you for that," she said.
