Stage 2 involves the construction of 628km of new lines, encompassing the line from Ghweifat on the Saudi border to the Omani frontier near Al Ain together with links to the UAE's three principal ports at Khalifa, Jebel Ali near Dubai and Mussafah. The project has an estimated pricetag of around $US 11bn.

Etihad Rail says it has informed bidders that tendering will be suspended while it reviews "the most appropriate options for the timing and delivery of this phase of the project."

"Etihad Rail is one of the biggest and most complex infrastructure projects ever undertaken in the UAE," says Etihad Rail chariman HE Nasser Alsowaidi. "As we enter 2016, we have been working closely with our partners and stakeholders to assess our strategic priorities for the year. As a result, a decision has been taken to suspend the tendering process for Stage Two whilst we review the most appropriate timing for this investment."

In December the UAE's Federal Transport Authority (FTA) granted Etihad Rail final safety authorisation for Stage 1, the 264km Shah - Habshan - Ruwais line, clearing the way for the start of commercial operations on the first phase of the network. Etihad Rail says the decision to suspend tendering for Stage 2 will not have any impact on its preparations for the launch of operations on the first phase.