The Government has sought further information about the condition of Lissadell House, Co Sligo, after an initial examination found the building was structurally sound.
Government sources said there was no decision in principle to purchase the historic house, family home of the patriot Countess Markievicz.
However, the request for further information implies that the Minister for the Environment, Mr Cullen, is moving towards such a decision. He is familiar with such projects as he was responsible for the state's purchase and development of Farmleigh House.
The sale of Lissadell, which is linked with the poet W.B. Yeats, has prompted many groups to call on the Government to purchase it for the State.
Sligo County Council and the local Fianna Fáil TD, Mr Jimmy Devins, want the house to be developed as a tourist attraction. An Taisce has said that the Government, together with local authorities and the private sector, should try to buy the property.
Government sources say Mr Cullen recognises the historical significance of the property.
While the Office of Public Works, which manages State buildings, said in recent weeks that it had no plan to buy Lissadell, Mr Cullen has argued that it would be remiss of him not to have the property examined.
However, he is conscious that any move to purchase the house must be sanctioned by the Cabinet in a situation where there is increasing pressure on the public finances. For this reason, he is keen to see a detailed plan.
While few doubt the merits of the property, which is a major example of early 19th century architecture, there is concern to develop a viable plan for its upkeep in the years after any State purchase.
Mr Cullen asked officials from the heritage section of his Department to examine Lissadell when it came on the market last month.
While the purchase price of about €3.5 million was not seen as prohibitive, there was concern around the ongoing cost to the Exchequer to maintain the house and the 400 acres that adjoins it.
While the initial examination found the houses's structure was essentially sound, an investment of about €5 million - over the purchase price - was necessary to improve the property and make it amenable to the public as a museum.
In addition, annual operating costs were estimated at €500,000. The State would have to meet some of that expense because the projected income from visitors at this stage would not meet that cost. With the tourist authorities and county council said to be working on a business plan for Lissadell, Mr Cullen is believed to be emphasising that that a high-quality management team should be appointed to run the house.
In addition, Mr Cullen wants to ensure a role for the Office of Public Works and for Sligo County Council in the running of the property.
Mr Cullen's officials are believed to have met in recent weeks with Sligo County Council, which has passed a unanimous motion urging the State to purchase the house.
While the county council and a group of local TDs are seeking a meeting with Mr Cullen, this has not yet been agreed.
Mr Devins said yesterday that he believed up to 100,000 visitors a year could be attracted to the house. This was the same number of people who visited Yeats's grave at Drumcliffe cemetery, near Lissadell. Stating that the house was only ever opened on an haphazard basis, Mr Devins said "it needs to be marketed as a tourist destination".
He added: "The State must buy it. Basically the business plan that will develop it as a major location, will I think, ensure that is does not become a major ongoing drain on the public purse."