Sefton Central Labour MP Bill Esterson warned the Conservative-led government was preparing to sell off parts of the greenbelt after George Osborne announced that there would be more changes to planning rules in favour of developers.
The Chancellor of the Exchequer said the latest changes to the planning rules would encourage councils to build on the greenbelt.
Bill Esterson said the announcement would make the fight against inappropriate developments on greenbelt in Sefton, including Formby, very difficult.
Bill said: "George Osborne has made it clear that he is encouraging councils to allow developers to build on the greenbelt.
"In March this year, the Tory-Lib Dem government introduced the National Planning Policy Framework which essentially gave the greenlight to developers to build on the greenbelt.
"This latest announcement goes even further.
"My fear is that this will be the death knell for the greenbelt and will open the floodgates for developers to build where they like, regardless of what opposition the community puts forward."
Bill said the Conservatives in Government were looking after their wealthy friends at the expense of places like Formby.
Bill said: "There is strong opposition to building on the greenbelt throughout Sefton. I have repeatedly raised these concerns with the government in parliament throughout last year's Core Strategy consultation when I was contacted by thousands of residents from every part of the constituency.
"We are now seeing a direct threat to the greenbelt in Formby where David Wilson Homes wants to build 300 houses on a stretch of land.
"Like many other developers, as well as appearing in the Sunday Times' Rich List, David Wilson himself is a Conservative Party donor. Developers have been lobbying the government to amend the planning rules to make it easier to build where they can make most profit.
"Greenbelt is a lot more valuable to developers because it gives them a greater return on their investment. But that comes at the expense of the greenbelt and the wishes of the community.
"When it comes to the Tory-Lib Dem government, money talks."
Bill this week met with the steering group behind the Formby Residents' Action Group who are opposing David Wilson's plans.
Bill said: "The Formby Residents' Action Group is doing a fantastic job in coordinating a campaign to oppose the proposed David Wilson development.
"I met the steering group this week and they have received the support of the bulk of the Formby community and are compiling a strong case to oppose the plans.
"I will continue to raise the issue in Parliament at every opportunity I can to show to the government what level of opposition there is to building on the greenbelt here in Sefton.
"We need affordable homes in Sefton. I have two children who will need somewhere to live one day. Many people cannot afford homes to rent or to buy. We will need more homes but in my view we need to build these on former industrial land or use the 6,000 empty homes in the borough.
"But while we have a government which is being financed by big business developers, they will be fixing the rules in the developers' favour."
Foirmby Resident's Action Group will be holding their next meeting on Friday, September 14 at Royal British Legion on Whitehouse Lane, starting at 7pm.