KPMG, joint auditor of Royal Dutch/Shell, has added to the crisis at the oil and gas group by refusing to sign off its accounts.

It is understood the firm, which jointly audits the company with Price Waterhouse Coopers, declined to approve the accounts, which were due out on Friday, because of worries about the quality of information it had received and mounting fears over potential liability to the Securities and Exchange Commission’s investigation of the group.

On Thursday Shell stunned the City by postponing publication of the results. At the same time it cut its level of proven oil reserves for the second time in three months, this time by 470m barrels.

News of the auditor’s rejection of the accounts comes just hours before a crisis meeting tomorrow that will take place between Shell’s senior non- executive directors and top City investors.

Lord Oxburgh, appointed chairman a fortnight ago, and Sir Peter Burt will be confronted by leading fund managers at a meeting at the Association of British Insurers (ABI) in London.

Shell’s management will be further embarrassed by the revelation that the Dutch royal family has lost nearly £250m through the collapse in the company’s share price.

The family is one of the biggest single shareholders in Royal Dutch. The family’s spokesman said its stake was “not more than 5%”, a figure that would equate to a loss since January of £244m.

Shell’s descent into crisis began in January, when it shocked shareholders by abruptly announcing that the company’s booked oil reserves would have to be reduced by 20%. The revelation led to the departure of Sir Philip Watts, chairman, and Walter van de Vijver, head of exploration and production. The group now faces investigations by regulators in Britain, Holland and the United States.

The company plans to issue its annual report in April, and the annual general meetings will take place in June.

Shareholders will tomorrow demand an explanation of last week’s announcement, and set out their views for change.

“New blood would improve shareholder confidence in the company’s will to change,” said Robert Talbut, chief investment officer at Isis, the fund manager. “There is a need for a slimmed-down decision-making body with a new chairman. We’d like to see headhunters appointed and a process started.”

A Shell spokesman said postponement of the accounts was the result of a decision to complete a detailed review of the reserves. It is being carried out by Ryder Scott, an independent consultancy.

“Once the board decided that it wanted to pursue a further in-depth review of the reserves position, it was necessary to delay publication of the annual report,” he said.

But it is understood that the auditors declined to sign off the accounts because they were not convinced that the information provided was reliable.

The firms are not legally bound to audit the oil reserves, but these figures are part of the notes to the company’s accounts and therefore still important. Their concerns are not without foundation. Milberg Weiss, America’s top class-action law firm, has already filed a claim against Shell that analysts say could top $1 billion (£546m).

Additional reporting by Dominic Rushe in New York