International oil groups mulling whether to bid for Unocal are having to balance their desire to acquire the $14bn energy group with a wish not to upset the Chinese government, bankers say.

China National Offshore Oil Corporation (Cnooc), one of the country's largest state-owned oil groups, has for months been exploring a takeover offer for California-based Unocal, inwhat would mark a landmarkoverseas expansion by a Chinese company.

Cnooc's interest has prompted a number of large international rivals, including Royal Dutch/Shell, BP, Eni, ChevronTexaco and a handful of US “independents”, to consider making offers of their own, according to people close to the companies.

But potential acquirers may be holding back out of a fear that any “pre-emptive” bid would damage their standing in Beijing.

Due to its soaring demand for energy, China is emerging as an increasingly important customer and place to do business for many international oil companies. “A very delicate chess game is being played around Unocal,” said one senior mergers and acquisitions banker in New York.

Some potential acquirers were thinking about a more aggressive strategy, while others were planning to be more prudent, he added.

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Rather than bidding for Unocal before Cnooc decided whether to put forward its own offer the more aggressive approach western suitors could wait for the Chinese group to drop its ambitions, and then make a move, another US energy banker said.

Long considered a takeover target among the US “independent” oil companies, Unocal's most attractive assets are in Indonesia and Azerbaijan.

It also has a collection of US assets, which are generally considered second-tier and might be sold in any acquisition by an international oil major.

The jostling for position around Unocal comes amid expectations of another round of consolidation among the US's many midsize independent oil and gas groups.

Thanks to soaring crude prices, the sector has piles of cash.

At the same time, companies are searching for ways to boost their reserves.

However, energy M&A bankers caution that sellers' expectations in terms of the price and conditions of a sale have also risen recently a point that has also been made in connection with Unocal.