The former Dunedin man was convicted in 1995 of murdering his parents, two sisters and brother and spent 13 years in jail before being acquitted in a 2009 retrial.
Friends of David Bain group head Catherine Spencer told the Otago Daily Times: "He is in town. He is just here visiting friends and that is all I am going to say."
She confirmed she was one of the friends he had visited.
Mr Bain was seen swimming at St Clair Hot Salt Water Pool with a female acquaintance, and he later relaxed at an outside table.
Supporter Joe Karam said Mr Bain had returned to Dunedin at least six times and enjoyed returning to the city.
"He still has lots of very, very close friends down there and he is regularly up and down."
Mr Karam confirmed the pair would attend The International Justice Conference at Perth in March, which is billed as the first time Mr Bain would speak publicly about his experience.
"It is the first time he has done a public address. Obviously, he has been interviewed on television a number of times over the years since he got bail, but this is the first time he has made a public address."
Mr Bain had written his speech "and he utilised my services for what they are worth, as well as other people he knows to help him fine tune it", Mr Karam said.
He has continued to work for the same Auckland engineering firm, specialising in marine engineering and fabrication, and lives in Kumeu.
Mr Karam said while he could not give specific details about his book, he confirmed it was to be published on Monday, February 13.
There also continued to be interest about a possible movie on Mr Bain's experiences, and "there has been discussions but nothing concrete or of a firm nature about anything".
Aside from the book launch and Justice Conference, the appointment of retired Canadian judge Justice Ian Binney would assess Mr Bain's compensation claims for wrongful imprisonment and conviction, Mr Karam said.
In March 2010 Mr Bain notified former Justice Minister Simon Power he would claim compensation.
