A protest rally at the weekend in support of St Luke's Hospital was told that the closure of the Dublin facility was motivated by profit.
About 100 people marched from St Luke's in Rathgar to the Central Bank building on Saturday, chanting slogans including "Save St Luke's" and "Harney must go".
The 179-bed cancer hospital is due to close by 2015 after its services have been transferred to other hospitals.
Rory Hearne, the chairman of the People Before Profit alliance, said that the sale of the 18.5 acre site would deliver a big windfall to the Government.
"The land is worth €180 million and we believe they plan to sell it off to developers. We believe this is what is fuelling the closure of the hospital," said Mr Hearne.
He said it did not make sense to close St Luke's to create a so-called "centre of excellence" at another hospital. "We believe St Luke's is a centre of excellence. Cancer patients have said they prefer to stay at home than go into somewhere like St James's."
A current St Luke's cancer patient, Marie Harford, addressed the crowd that had braved the chilly Dublin weather to support the hospital.
"I'm just an ordinary Joe, I've got six children, I was diagnosed two years ago with cancer and I have third-stage cancer and if it wasn't for St Luke's I wouldn't be here. I would be dead. It's as simple as that."
Dr Peadar O'Grady, also of the People Before Profit alliance, called for the Government to fulfil its promise to provide 3,000 extra hospital beds.
Ryan Meade, an adviser to Green Party Minister John Gormley, told the rally that the Greens would do everything they could to stop the hospital from being sold to developers. He said Mr Gormley supported the campaign to keep St Luke's open, and was opposed to the site's sale to developers.
"John Gormley strongly believes this will not happen," said Mr Meade. "St Luke's already has one key advantage. It is a centre of excellence already."
Several gardaí accompanied the protest march and were called into action only when two drunks had to be gently moved along.