Labour has accused the Government of having serious questions to answer following the Amgen announcement, while Fine Gael has called for immediate action to find alternative projects for the area.
"It is quite clear that this was nothing more than an election stunt from Fianna Fáil. Time and time again Minister Martin pointed to Amgen as a prime investment in terms of jobs creation, yet there were rumblings for a long time from people in the area and employees at the site as to the viability of the project," said Cork East Labour TD Sean Sherlock.
He said there was no way Amgen was ever going to build a $1 billion plant in Carrigtwohill when the company was already in freefall.
"You would not have to be a rocket scientist to figure out this would put the Cork plant in jeopardy, yet this Government and its Minister for Enterprise, Trade and Employment refused to come clean and admit that this development would never happen."
Fine Gael enterprise, trade and employment spokesman Leo Varadkar called on the Government to immediately seek alternative investors for the region.
Mayor of Midleton Cllr Billy Buckley said people had been fearful for the project ever since the postponement announcement last April, but the announcement it still came as a huge blow to Midleton and east Cork.
Cork Chamber of Commerce chief executive Conor Healy said it was particularly disappointing news, but stressed it did not mean Ireland was an unsuitable business environment for biopharma firms. Others such as Eli Lilly and Centocor were expanding.
A Cork County Council spokeswoman declined to say how much money the council had spent on preparatory works on the Amgen site pending a meeting today between council officials and Amgen representatives.