If permission is granted the development would have 16 bedrooms
Residents in Leigh-on-sea are opposing proposals for a new hospice for terminally ill adults.
The Havens Hospice charity would like a new £15m building on green belt land near the railway station.
Campaigner Mike King told BBC Essex: "It is raping what is natural land and putting a building on it."
Havens Hospice chief executive Andy Smith said they needed a site that would provide them with a state of the art hospice for years to come.
"We've talked to people who have built modern hospices, we've talked to our patients," said chief executive Andy Smith.
"We've put together what we think is requirements for a piece of land which will enable us to build a hospice of the type that we want which will deliver the services now and into the future."
The hospice said they had been looking across Southend for suitable land, including nine sites in detail.
"We know its on the green belt, but in terms of giving us the best fit against the requirements that we've been looking for this is the one that comes top of the list," said Mr Smith.
Local resident Mike King is one of the people leading the challenge to the plans.
"We are great supporters of the hospice," he said.
Mr King believed it was 'the thin end of the wedge', and the group fears if the hospice plans went ahead, there will be further development of the land.
"We're looking into other examples across the whole of the UK, where the 'rape' of green belt land has taken place," said Mr King.
"The problem is, if this was the only site that could be built on for the hospice then it would be very different.
"That really is not the case, they've got land adjoining their existing hospice on which, I understand, they have an option.
"One would have thought that having the two together would be advantageous for them."
Mr Smith told BBC Essex because they own the land at Little Havens, using it for further development has always been an option.
However, the site is not as well served by public transport.
"One of the key things that we find out by talking to patients and their relatives is they want to be somewhere they can still experience life going on and are still part of the local community," said Mr Smith.
If permission is granted, it is hoped the new building would be open by 2015.