Sefton Central Labour MP Bill Esterson said residents have a mountain to climb in opposing plans to build a care village on greenspace in Maghull after Tory-Lib Dem government planning changes re-opened the door to the previously rejected plans.
The plans for the unit were rejected by Sefton Planners as the land is designated as 'urban green space'.
But the developer is in the process of resubmitting the plans because of changes to the country's planning laws which give developers an automatic default approval for development.
The changes were rushed through Parliament just one week before the Damfield Lane developer made its new application.
Bill Esterson, who has been fighting against the Tory-Lib Dem government planning law changes, said the planning reforms made things very difficult for campaigners opposing the Damfield Lane development.
Bill said: "Sefton Planning Committee turned down the original planning application for a care village, thanks in part to the information which residents were able to provide to your ward councillors and thanks also to the hard work of Cllr Patrick McKinley on your behalf. The committee was able to find planning reasons for rejecting the application.
"Planning applications can only be decided on planning grounds and these are set by the government. Even if it is local planning authorities who make the decisions, their hands are very much tied by government rules. So finding grounds for rejecting the plans first time round was a big effort all round.
"But a few weeks ago, the government changed the planning rules which means that planning decisions are now to be taken with a presumption in favour of development. In other words, developers are given a default yes.
"This means it is far more likely that planning applications will be approved either by a planning committee or by a planning inspector on appeal if a planning committee rejects a planning application.
"That is unless the community can come up with watertight planning reasons for objecting to the plans."
The MP said the rules favour developers who have the financial resources to put their case, while the community is left to put their arguments without having expensive legal backing.
Bill said: "Most of us in the community aren't legal experts, so it is obviously very difficult. But what we do need to do is work together to ensure that these government changes don't end up having a damaging effect on our community.
"That's what the residents who are opposing the Damfield Lane care village have been doing together with Sudell Labour Ward Labour Councillors Patrick McKinley and Lynn Gatherer.
"But it is also important to recognise that because of what the government has just done, the planning committee may not be able to reject the new planning application. If the committee rejects the application without planning reasons, then a planning inspector could overturn the decision and make Sefton Council pay the costs of the appeal. Such costs could be as much as £250,000, something Sefton Council would struggle to afford given the scale of cuts from that same government.
"Whatever the outcome of the planning process, I will continue to challenge the changes in planning rules brought in by the Conservatives and Liberal Democrats in government. I have warned them for the past year that the new rules would give developers way too much power. If the plans do go ahead I will also make sure that we press United Utilities and Sefton Council on drainage, traffic and any other issues.
"the future of Damfield Lane could well be an example of how the Tory-Lib Dem planning changes will impact on communities not just here in Maghull, but also throughout Sefton and the rest of the country."