POOLE Town will not be permitted to take part in the National South play-offs should they retain their place in the top five.
The club plans to appeal to the Football Association.
In order to participate in the National South and National North play-offs and to play at National League level, clubs must have 500 seats under cover.
It is believed this regulation is over and above FA ground-grading rules.
Poole vice-chairman Chris Reeves told the Daily Echo: "We have had a letter to say that in the league's opinion, we are not eligible to play in the play-offs.
"I'm in touch with the FA with regard to an appeal."
Darlington will not be allowed to take part in the National North play-offs because their ground does not have the required amount of covered seating.
Like Poole, the Quakers are set to appeal and have been in contact with the Dorset outfit over their predicament.
At the end of last month, the Black Gold Stadium passed an FA ground-grading inspection which ensured Dolphins received the green light to remain at step two level.
The club had carried out extensive improvements including installing low-level terracing, re-positioning a floodlight and putting in extra turnstiles, at a total cost of around £170,000 with no facility to receive a Football Foundation grant.