Sefton Central Labour MP Bill Esterson told hundreds of people at a Campaign for the Protection of Rural England debate that the borough's greenbelt must be saved.
Speaking at the event at Crosby Civic Hall on Friday evening, Bill said the government was giving the greenlight to developers to build on our greenbelt.
Hundreds of people from throughout Sefton, including Formby, Crosby, Maghull, Lydiate, Hightown, Melling and Aintree, attended the debate which also included a representative from Bellway Homes.
Speaking during the debate, Bill said: "There is a real challenge to find decent housing for future generations. And I recognise that Sefton has to face that challenge.
"But I'm here to represent the people of Sefton Central and the over whelming view is that they want to protect the greenbelt.
"Our greenbelt here in Sefton is used for leisure pursuits, which brings lots of people into the borough. It is used for agricultural land. Just look at how much food prices have gone up and how we'd like to grow our own food. We cannot allow that land to be destroyed. Once it's gone, it's gone.
"I fully appreciate that we need to build affordable homes here in Sefton for our future generations. I have two children myself and I'd like to think that when the time comes they will be able to buy a property.
"But we do have a number of other options other than having to build on our greenbelt. For instance, Sefton has more than double the national average of empty houses. I am pleased that the process is now started to reclaim that property. We have brownfield sites which can be built on."
Bill said Sefton needed to close the door on allowing the greenbelt to be built on.
He said: "Eric Pickles assured me during a debate in Parliament that the greenbelt land was sacrosanct, but that assurance was smashed when the government report was leaked which gave advantage to developers to build on our greenbelt land.
"It will be made all the harder to reject a developer's application to build on greenbelt if Sefton Council gives the greenlight to building on greenbelt land as part of the core strategy.
"The council needs to find a way of doing this without approving option 2 or 3 of the core strategy."
Bill said the demand for new housing needs to be reassessed in Sefton.
Bill said: "We are told that Sefton needs 480 new homes per year. but I think it's about time that we revisit these figures and challenge whether we need this number of new houses at all.
"Wirral has certainly managed to find a way out of building this number of houses. We need to look at how they have done it. And we need to speak to local authorities around the country so we can share knowledge on this subject and find out how they have managed to protect the greenbelt.
"This core strategy needs to be a region wide study which takes into account land throughout the North West, instead of authorities looking at their own areas in isolation which is just crazy.
"My reading of the core strategy leaves me asking questions about jobs. The cuts are hitting and people need jobs. We need to bring in investment to the borough.
"There clearly needs to be an economic strategy."
The MP said he heard arguments during the meeting which he will take up in Parliament.
Bill said: "I'd like to thank the CPRE for organising this debate. We've heard some really good ideas which need to be put to the council and I urge people to take part in the survey and urge the council to stick to option one of the consultation.
"I will take away a number of points which were raised and take them forward any any other issues nationally.
"We heard concerns during tonight's meeting as well as at the many other meetings around the borough about the fears that the infrastructure will not be able to cope. This includes the impact on the sewers as well as the general drainage throughout Sefton. Then of course there's the issue about building on the floodplain.
"The changes which this government is introducing are making it easier for developers to build on the greenbelt. That needs to be opposed.
"The government should be looking at encouraging building on brownfield sites and encouraging decontamination of land for construction instead of opening the door to the decimation of our countryside."