APA Secretary Wayne Flint says his group which is also known as the Emergency Medical Service Protection Association (EMSPA) has acted as a union since 2009.
"We seemed to fill in the gaps which HSU either didn't bother to or couldn't fill for paramedics," he said.
HSU East has faced ongoing scandals about its finances, and all positions were vacated when it was put in administration last year.
"I would have to say with respect to what is now it before the courts and a matter for the courts, is that the media uncovered and pretty much kicked them around enough that I wouldn't need to make any comment whatsoever," he said.
The new leadership of the HSU, under Gerard Hayes, is promising greater autonomy for the paramedics section - which is about 5 per cent of the membership.
Mr Hayes disputes that union has not done well in the past.
"Many outcomes have been achieved and we are now focused on maintaining a lot of those outcomes in a very harsh industrial climate that has been set up by the O'Farrell Government," he said.
He says a small union makes no sense.
"We are a union of 30,000-strong members," he said.
"Paramedics have been part of this union for fifty years, not five minutes, and what they are proposing is to formulate a group of some 1500 people to create a boutique union."
It was not until legislation passed state parliament last year that EMSPA could apply to become a union, and late last week the State Government published a regulation to remove any doubt that the organisation could be registered.
Secretary Mark Lennon says it is supporting members rather the union itself.
"We don't think it is in the long-term interests of ambulance workers or health workers generally for there to be division amongst those workers, particularly when they are facing such huge challenges with the O'Farrell Government and their health cuts," he said.
Mr Lennon says Unions NSW is working with the HSU on reform to its governance, and re-affiliation will be considered when that process is complete.
The Paramedics Association's Wayne Flint says he cannot understand that position.
"For some time they have been a body that the unions don't want to be publicly associated with, and we now see Unions NSW moving to protect their status," he said.
He says many people in the Ambulance service are not in a union because they do not want to join the Health Services Union.
"We see that we are bringing membership back to the unions. We want to sit down beside them but we don't want to be a part of them," he said.