The mining company said it now expects the copper mine to cost about US$6.4 billion and produce its first concentrate in the fourth quarter of 2017.
That compared with an earlier estimate of US$6.2 billion and commercial production in 2016.
However First Quantum said once the mine is in production it is expected to produce about 320,000 tonnes of copper annually on a life-of-mine basis, up about 20 per cent from earlier estimates.
The open-pit copper mine in Panama, which is expected to operate for 34 years, is also expected to produce 100,000 ounces gold, 1.8 million ounces silver and 3,500 tonnes molybdenum per year.
The new guidance for Cobre Panama follows a detailed review by First Quantum, which acquired the project when it took over Toronto-based Inmet Mining last year.
First Quantum said it has changed the plan for the project from an out-sourced approach to one that will see the company do the work itself, with outside engineers and contractors used only for specific tasks.
The company also announced a refinancing plan to secure the proper funding for the project.
"The re-engineering of the Cobre Panama project has resulted in a very much larger project at substantially lower capital intensity and with a considered but clearly defined timeline to completion," First Quantum president Clive Newall said.
"The restructuring of the balance sheet has ensured that the project is well-funded and can be progressed expeditiously toward becoming one of the pillars of the company's future."
First Quantum holds an 80 per cent stake in the project with the remainder owned by Korea Panama Mining Corp.
The company, which produces copper, nickel, gold, zinc and platinum group metals, has seven mines and five development projects around the world.