Talk of a national second division with promotion and relegation to and from the A-League may be raging in football circles, but one former club boss says it is unrealistic in the near future.

Lyall Gorman, former chief executive of Western Sydney Wanderers and Central Coast Mariners, and former head of the A-League, says a national second division is simply not financially viable.

While the Cronulla Sharks boss describes a national second division as a "very admirable plan", Gorman believes it is some way off.

"It's the financial model," he said. "How do you move from zero to compete with what Sydney FC or Melbourne Victory are spending today? It's probably closer to 20 [million dollars] than it is to 10. So how do you move from a zero base to compete with that? It's quite a journey isn't it?