Merger candidates Price Waterhouse and Coopers & Lybrand expect to receive a detailed statement of objection from the European Commission later today. A similar report from the US regulatory authorities is expected in the next few days.

The firms' combined audit strength in the banking, financial and insurance sectors in certain European countries is understood to top the commission's list of concerns in the document, which is up to 60 pages long. PW and Coopers must respond within two weeks to the commission's concerns with their proposed remedies.

Accountancy Age understands the document - which by European law must contain all the commission's possible concerns - will also be sent to 'interested parties' including Big Six rivals. The merger firms are scheduled to attend a hearing at the commission on 7 April to explain their proposals.

But a PW spokesman remained confident the merger would be given the all-clear by the regulators. 'The commission was very tough on KPMG and Ernst & Young's planned merger and gave clear signals it would not be passed,' he said.

'We have not received any such signals and we believe it has much less of a problem with us.' He added that much of the 'remedy submission' and hearing would be used to convince the commission that the firms were not dominant in the sectors concerned.

The EC's objections come as the Big Six's dominance in the field of tax advice was challenged by this week's launch of Chiltern Group, an independent tax consultancy formed following a management buy-out from UBS.

Chiltern, which supplies tax advice to clients including Prudential and Hogg Robinson through its UK subsidiary Williams Jeffery Barber, said it planned to target dissatisfied clients of the merging Big Six firms.

Andre Bischoff, Chiltern MD, said the group would steer clear of audit and general practice work.

'Our independence will allow us to give the very best advice for business without any of the potential conflicts that can arise in audit-based practices,' he said.