Wrexham have criticised Peterborough after the Championship club announced they had reached an agreement to sign Dragons captain Nat Knight-Percival.
Posh director of football Barry Fry is quoted in the Peterborough Evening Telegraph saying Knight-Percival will join them on a free transfer in July.
The 25-year-old has been offered a new contract by Wrexham but has so far not revealed where his future lies.
But Wrexham have said Posh should not talk about a player under contract.
"We have a strict policy that we do not speak publicly about players who are under contract with another team. Sadly, we cannot control how other clubs conduct themselves in such situations," said Wrexham chief executive David Roberts.
Posh owner Darragh MacAnthony admitted the scenario was "not fair" on the Blue Square Bet Premier side.
He said on Twitter: "It came out at weekend from an agent in the paper hence why Barry had to clarify it.
"I'm not happy that's come out as not fair to his club whilst in promotion battle. So no comment until season is over."
Knight-Percival has been outstanding for Wrexham this season, forming a formidable centre-back partnership with Mark Creighton that has seen the Dragons concede the fewest number of goals in the Blue Square Bet Premier.
He was converted from a midfielder into a centre-back by former Wrexham manager Dean Saunders and caught the eye of Peterborough manager Darren Ferguson in his side's FA Cup third round match with Championship side Brighton.
"Nat has been an integral part of our success this term and it is only natural that clubs from higher divisions have been monitoring his progress," added Roberts.
"Indeed, we turned down a six-figure offer for him back in January because of our desire to win promotion back to the Football League.
"We fully understand why he has kept his options open and, if he does decide to move on, then it will be with everybody's best wishes.
"We know Nat is fully committed to seeing Wrexham achieve promotion this term and that he is determined to play a full part in ensuring that happens."
Wrexham are currently second in the table, eight points behind leaders Fleetwood but with a game in hand.
Only the league champions are guaranteed promotion, with the four teams directly below given a chance to join them through a play-off.