On Monday, the company issued a statement that in the light of the downturn in the economy, it was reviewing its strategy.
While it has cast doubt on the move to Leixlip and with it 170 long-term jobs, the company has not said it is not relocating
some of its operation to the north Kildare area.
It will be several months before the review is complete, said Diageo.
It said: "Diageo has a long-term strategy to ensure its Irish brewing operations are internationally competitive in support of its global beer strategy.
"In May 2008 Diageo Plc announced a n650m plan to develop a new brewing centre of excellence in Ireland, which was scheduled to be completed in 2013.
"As result of the current difficult global economic situation, which affects both Ireland and the main international markets to be served by the new operations, Diageo has decided to conduct a re-evaluation of this brewing investment programme in order to ensure its scope remains appropriate in the changed economic environment.
"The evaluation is expected to run for several months and the outcome will be communicated to staff and other stakeholders as soon as possible."
A spokesperson for the company said that it did not say it was not moving to the site and it still planned to locate its long-term international brewing operation in Ireland.
The spokesperson also said that it had not yet bought the land from Desmond Guinness and Kildare County Council but that a lot of scoping work had been carried out.
Last September there was widespread welcome for the decision by Diageo that it has entered into agreements to acquire a 73-acre greenfield site in Leixlip.
The company said then that it intended to build a new state-of-the-art brewery but it plans to retain its historic links with St. James Gate.
This proposed development would represent the next stage of a €650m capital investment in its brewing operations in Ireland announced by it in May 2008.
Diageo anticipated that the new brewery will be completed by 2013 and will be called the 'Arthur Guinness Brewery'.
Once commissioned, the new brewery - in conjunction with the remodelled St. James's Gate brewery - would transform Diageo Ireland's current brewing operations into a two-brewery centre of excellence to support the growth and development of its domestic and global beer business.
It confirmed that most of the proposed site, 50 acres, will be purchased from the Guinness family, direct descendents of Arthur Guinness.
The remaining 23 acres would be bought, subject to Council approval from Kildare County Council.
The proposed site adjoins the N4 motorway, the River Liffey and Hewlett Packard.
The company said that Leixlip would be the biggest Diageo brewery in the world and the largest in Ireland.
Commenting on the announcement then, Brian Duffy, Guinness Global Brand Director and Chairman of Diageo Ireland said: "This site announcement is a truly significant decision by Diageo. Not only are we demonstrating our commitment to Ireland, we are also staying true to the roots and heritage of the Guinness brand and Arthur himself. A new world-class brewery built in a location with such close historical links and with the full support of the Guinness family, is a remarkable milestone in the life of a remarkable brand and something I feel that only Diageo with its sense of heritage and tradition would do."
The company thanked both the IDA and Enterprise Ireland who worked with Diageo to identify and secure the most suitable property solution for the new brewery.
It has been anticipated that the plant will employ 170 workers directly and will provide a considerable boost to the construction industry in the area and there will be a spin off of indirect jobs locally.
Kildare North Labout TD, Emmet Stagg has expressed his deep disappointment at the announcement.
"Whilst the outcome of the review will not be known for a number of months I am calling on Diageo to fulfil the words of their Irish chairman when announcing the details of the new brewery last September that they were not only demonstrating their commitment to Ireland but that they were staying true to the roots and heritage of the Guinness brand and Arthur himself," he said.
The Labour TD called on the Tanaiste to hold high level talks with Diageo Ireland to ensure that the investment proceeds and remains in the home of Guinness.
"The live register figures for the Maynooth labour exchange has more than doubled in the last 12 months going up from 1,767 people signing on to 3,256 people signing on and the new brewery gave some hope of reversing the tide of unemployment given the fact that the Government seems incapable of managing the economy or reacting to mass job losses," he concluded.
