Originally the target date for the IPO was 2018, but earlier this year Saudi Arabia announced the project would be delayed.
Prince Mohammed said the delays originated in mid-2017, when Aramco started talks to buy a majority stake in Riyadh-based chemicals company Sabic, a deal that has been estimated to be worth US$70b.
"Everyone heard about the rumours of Saudi Arabia cancelling the IPO of Aramco, delaying that, and that this is delaying Vision 2030," said Prince Mohammed. "This is not right."
The crown prince said it would have been unfair to go ahead with the listing only to surprise investors soon after with a big deal in chemicals.
US banks JPMorgan Chase and Citigroup are working on the IPO.
Prince Mohammed has now given Saudi Aramco less than three years to complete both the Sabic acquisition and the IPO. He believes the Sabic deal will close next year. Aramco will then need a full financial year before it can go ahead and sell shares to the public, according to the crown prince.
Many analysts say his US$2t valuation is too ambitious and could become a key sticking-point in the share offering, with some saying US$1t is more realistic.
Another problem is the increased scrutiny that would be required as part of a public listing.
Both London and New York are vying to be the venue for the listing.
In June this year the London Stock Exchange created a new category to make it easier for Aramco to comply with requirements.