The six men wearing Australian flags and handing out flyers to new citizens were barred from entering the ceremony at Coburg Town Hall in Melbourne's north on Friday.
"We are protesting the council's decision to not refer to the phrase 'Australia Day' in the official ceremony," convicted racial vilifier Mr Erikson told AAP.
A heavy police presence surrounded the ceremony and prevented the men from going inside.
More than 90 people were at the town hall to have their citizenship conferred.
Moreland Mayor John Kavanagh paid his respects to Australia's first people at the ceremony.
"Furthermore I acknowledge today is a difficult day for many Aboriginal and Torres Strait Islander people," Mr Kavanagh said.
Moreland is one of three Melbourne councils which is not recognising Australia Day on January 26 in a move that has sparked national debate.
"Inside this council they don't represent majority of Australians," Mr Erikson said.
The protesters left once the ceremony started.
In the city, thousands gathered outside parliament house carrying banners reading 'Survival Day' and 'Day of Mourning'.
Australian Greens leader Richard Di Natale, and Victoria's first female indigenous MP Lidia Thorpe were among the crowd, monitored by a heavy police presence.
