This year is also the centenary of the emergence of the faith in Auckland.
There is now a Baha'i New Zealand organisation.
Mr Bain said he came back from England excited about this faith but found "no receptivity among family and friends" back then.
"I could find no one who knew anything about it at that time."
Today, it is likely to still be a little-known faith in Wairarapa, with an active core of about a dozen local people.
He said it was overseas groups that had helped safeguard the interests - and the lives - of Baha'i followers, who he said numbered about 300,000 in Iran.
"The fact is, nothing has changed.
"While they are not hanging people today, they are holding them in the most atrocious conditions, in some of their toughest prisons."
The public meeting is at 7.30pm on July 9 at Masterton Community Centre, 41 Perry St.