The Independent Electoral Commission (IEC) has rejected the registration of Action SA as a political party.
This decision was based on similarities with the Party of Action (POA), and the use of the South African flag in the logo.
Herman Mashaba applied to the IEC for registration of his party earlier this month.
In a statement, Action SA says the IEC has acted irrationally and it is appealing the decision.
The POA have accused the former Johannesburg mayor of stealing its logo and appropriating its name when he launched Action SA party.
Established in 2018, POA has a membership of around 100,000.