"I would be very surprised if the commission raised any big objections," an official at a rival firm said on the condition of anonymity, noting that currently no company held more than five per cent of the market worldwide.

The European Commission's objective is to prevent creation of dominant positions in the 15-nation European Union. It is not size that matters, but whether the merging companies' activities overlap significantly.

The commission has only blocked 10 mergers since 1991, when it became the EU's clearinghouse for mergers and acquisitions, and conditions imposed on many others were often minor.

Two years ago it gave its blessing to the merger of Sandoz and Ciba-Geigy which created Novartis, contenting itself with an undertaking relating to the licensing of products for the treatment of fleas and ticks in cats and dogs.

This was despite it deciding on an in-depth probe into the deal, which usually indicates strong concerns over reduced competition.

Perhaps in a move to avoid a full probe, which lasts up to five months from the filing of the deal, Astra chief executive Hakan Mogren and Zeneca's Sidney Lipworth met with EU Competition Commissioner Karel Van Miert this week.

Such pre-application talks are not unusual with big mergers and acquisitions and indicate the companies' willingness to address any concerns at an early stage.

The commission would not comment on any potential problems. Industry officials and lawyers, on the other hand, were at pains to identify any significant overlaps in the myriad products made by both companies.

But they expected commission regulators would look closely at the companies' combined holding of leading cardiovascular products and review whether Astra's strength in anti-ulcer drugs achieved through its Losec product would be strenghtened.

Losec, however, was at the end of its patent life, and could be copied widely from the expiry of its protection rights in 2001, they said.

The commission was also set to consider the constraints placed on drugs manufacturers by overstretched national health systems which would act as a moderator for prices.

The creation of AstraZeneca, as the new company would be named, was not the only tieup in the sector.

Germany's Hoechst and Rhone-Poulenc of France will also be filing their life sciences merger for EU approval and the same was true for an all-French deal between Sanofi and Synthelabo SA.

Such an avalanche of mergers, which is not limited to the pharmaceuticals sector, is one element that might complicate the regulatory review as commission officials will struggle to assess the impact of each deal on a multitude of drugs while bearing in mind the ongoing industry consolidation.

The oil sector is also undergoing a major consolidation drive with Exxon and Mobil of the United States, and Petrofina of Belgium and France's Total announcing mergers closely on the heels of the marriage between Amoco and British Petroleum.

Mindful of the spectre of the auditing merger wave a year ago, observers are growing increasingly nervous that in some sectors the number of players may be falling to a level unacceptable for regulators.

KPMG and Ernst & Young called off a merger plan after the commission expressed concerns about the reduction of the so-called `Big Six' worldwide auditing firms to four -- Price Waterhouse and Coopers & Lybrand had been first to the commission door and eventually got clearance.

Apart from this sector, the only other sectors singled out by Van Miert as having reached an unacceptable level of concentration are aircraft manufacturing and the making of aircraft engines where the number of players has been reduced to two, especially with regard to large airplanes.