Tory councillors have criticised Labour's Paul Birch for "leaking" details about the Seven Cornfields in Wolverhampton.
He said on Facebook that the area between Penn and Sedgley would not be included in the Black Country Plan. The draft plan is set to be officially announced on Friday.
But Dudley Council's cabinet member for regeneration, Councillor Simon Phipps, said Councillor Birch's move risked undermining the whole process; which aims to find land for new homes in a joint effort by Dudley, Sandwell, Walsall and Wolverhampton councils.
However Councillor Birch, who represents Blakenhall ward in Wolverhampton, said there was no risk as the Seven Cornfields would remain green belt.
Councillor Phipps said: "We are in the middle of an incredibly complex Local Plan setting process, a legal requirement which, if we do not get it right, could lead to disastrous consequences.
"Our every move is being scrutinised by developers and it will ultimately be the Planning Inspectorate who decides if we have followed the legal process correctly.
"Getting this wrong could mean the inspectorate making decisions about where to build in our local green belt, rather than decisions being made by elected councillors.
"Councillor Birch's actions are irresponsible and dangerous. He is threatening the very thing that far more long-standing councillors than he have been working on for years.
"That is protecting the most precious and historic green spaces for future generations to enjoy."
However in response Councillor Birch said: "There is no risk involved because the Seven Cornfields is not in the Black Country Plan. Therefore, it remains green belt and cannot be built on.
"People have had a really bad year, we have lost a lot of people that are close to us, people we love. They deserved some good news."
Councillor Phipps made further claims that Councillor Birch had leaked details about another development being saved, one in Dudley regarding Foxcote Farm in Wollescote.
However Councillor Birch denied this and accused the Tories of "fabricating" social media posts claiming he had.
He believes the social media account was fake. The Express & Star made attempts to contact the user.
One post, seen by the Express & Star, showed a Facebook user claiming he had spoken to Councillor Birch about the development being saved, with the post published on a community group.
Councillor Phipps said: "Not only has he leaked details of the draft plan in his own borough so he can attempt to claim political credit for what was a community-wide campaign, but he has also been linked to the leaking of details of the draft plan in Dudley too.
"Councillor Birch should not have details about the draft plan in other boroughs, so I can only assume someone within Wolverhampton Council's cabinet or senior officers have given councillor Birch these details.
"A thorough investigation into his actions must take place Councillor Birch should be suspended and excluded from receiving future confidential briefings on this subject, for the good of the green belt which he is threatening just so he and his party can score a few political points."
In response to this claim, Councillor Birch said he had referred himself and the matter to Wolverhampton Council's monitoring officer.
He also suggested that Councillor Phipps should refer the matter to West Midlands Police.
Councillor Birch said: "Either Councillor Phipps or one of the Conservative group fabricated this in order so they could get into the story.
"How can Dudley Council talk about the Seven Cornfields which is not in their authority?
"He is accusing both of his officers and ours of a criminal offence under legislation introduced in 2010.
"Councillor Phipps should be making a complaint to the police. I am willing to defend myself in this by giving an affidavit.
"I have reported this to my monitoring officer, asked my monitoring officer to investigate it.
"He should also report himself to the monitoring officer. Monitoring officers make decisions independent of him and I about who is right."
The leader of Wolverhampton Council, Ian Brookfield, also defended Councillor Birch, saying none of his councillors had leaked details about developments in another Black Country borough.
Councillor Brookfield said: "I can absolutely guarantee that Paul Birch hasn't leaked any of the other authorities plans to the press or residents, for the very simple fact he doesn't know them, he hasn't had them, he hasn't seen them.
"None of my group have seen anything other than Wolverhampton [the city's part of the Black Country Plan]."
Councillor Simon Bennett, deputy leader of the Wolverhampton Conservative Group, said a briefing with council officers about the Black Country Plan had been cancelled on Monday night.
He said all further briefings were suspended while "cross-authority issues are addressed".