Expanding Ulster University's Magee campus would be a "game-changer" for Londonderry, the Assembly has heard.
MLAs were told the multimillion-pound development, which had been under threat because of budget cuts, was the only way of redressing the economic imbalance in the North West.
SDLP MLA Pat Ramsey said: "There is nothing more important to Derry at the present time.
"The most important regeneration project that could ever take place in Derry is the expansion to Magee. Everybody has said it."
Last month Employment and Learning Minister Stephen Farry said he would bid for the £11 million needed to pay for the expansion.
Mr Ramsey added: "The time for talking is long gone. It is time for this Assembly to put its money where its mouth is. If we are serious about redressing the issues of economic imbalance, clearly and without a doubt this is the best move.
"The development of the Magee campus is the most clear, most obvious investment in the future of lives of people in the North West."
The Assembly was debating a motion calling for the Executive to prioritise the expansion at Magee.
Sinn Fein MLA Michaela Boyle described the development as a "central plank" for regeneration.
"I am fully in support of the expansion of Magee," she said. "The expansion of Magee is a central plank for regional economic regeneration.
"We need a unified voice coming out of the North West region demanding what should have been delivered 50 years ago."
Mr Farry said he was committed to expanding the university "in principle" but warned that the project faced significant challenges including financial pressures.
"In principle, I do want to see the expansion of the Magee campus of Ulster University.
"I am committed to doing what I can to make this a reality, subject to the discipline of the business case and economic appraisal and, crucially, the availability and sustainability of resources."