Hearts make an official approach for Porter
The move came just hours after McGhee had complained that while Csaba Laszlo had publicly stated his interest in Porter, the Hearts manager had refused to confirm that interest when the two bosses met after the recent league match between the teams.
"I asked the manager when he was in my office after the game if he was interested in Porter and he didn't say he was," McGhee said. "Normally you make an official bid and then it's reported.
"As I said at the time, put your money where your mouth is. If they are going to make an offer then make an offer. Don't mess about playing games.
"The situation is transparent. Porter is out of contract in the summer and they know that the lad is looking around; he's playing well, he's scoring goals and he is going to attract attention.
"We are a club that might have to sell. So if they want him, come and get him."
Hearts are unlikely to be the only team to bid for Porter this month. Championship sides Sheffield United and Norwich City have also been linked with a move for the Wigan-born forward, while Slavia Prague have also registered an interest with Fir Park bosses.