Saudi Arabia’s Arriyadh Development Authority has extended the closing date for five construction contracts for the $7bn-8bn six-line Riyadh metro project.

Contractors now have until 20 February to submit their bids, according to a source familiar with the project. This is the third time that the submission date has been extended. The original bid deadline was 1 December 2012.

The original extension was granted after companies requested more time to prepare bids.

Four consortiums have already been prequalified for the metro scheme. The project is being tendered as five major design-and-build packages, with lines 1 and 2 as one package, and the other lines tendered as single packages. Each package includes the supply of rolling stock.