Alex Davies, 27, is accused of being a member after the group was banned as a terrorist organisation in 2016
The alleged co-founder of National Action has denied being a member of the neo-Nazi group after it was banned by the government.
Alex Davies, 27, pleaded not guilty to membership of a proscribed organisation on Friday.
Being a member of the group was not a criminal offence until the 2016 ban.
Mr Davies, of Uplands in Swansea, appeared at the hearing via video-link.
Judge Mark Dennis QC freed him on bail ahead of a trial due to start on 19 april.