A Saudi Aramco spokesman, according to Reuters news agency, has said that a series of options are being actively being considered for the IPO and that a decision has not yet been made yet while the IPO option “is still on track”.

Aramco's dual listing on the Saudi stock market, Tadawul, and an international exchange had been earmarked for 2018 by the Saudi authorities - with stock markets in New York, London and Asia all vying for the offering.

A decision on which exchange would secure the offering has still not been made, with top members of the Saudi royal family preferring New York and Aramco's financial and legal advisers advocating London.

The sale next year of just under five percent of Aramco forms the cornerstone of the oil-rich kingdom's reform programme to wean the economy off its reliance on oil prices.

Until 2014, oil income made up more than 90 percent of public revenues.

The kingdom has since concentrated on diversification, including plans to introduce value-added tax as well as the Aramco IPO.

Oil prices have partly recovered after major producers inside and outside OPEC, including Saudi Arabia, agreed last year to cut output by 1.8 million barrels per day.