BP will go head to head with a Russian investor group in a Siberian courtroom this week, in an attempt to overthrow a ruling that has forced 148 of its top employees to stop work at its TNK-BP joint venture.

The oil giant is challenging an injunction raised by Tetlis, a small Moscow brokerage, which claims that BP is overcharging the joint venture for the services of expatriate engineers and geologists.

BP charges $120m (£61m) to the joint-venture company every year to pay salaries, living allowances and other perks to the 148 workers – the same people who were forced to stop work earlier this year after visa problems.

Tetlis claims the staff charges represent an additional dividend being paid to BP out of the joint venture, over and above its agreed entitlements.

BP disputes the claim, but Tetlis won an injunction last week. The allegations will be fought out in the Tyumen arbitration court on Tuesday.

BP owns 50% of the joint venture, with most of the rest shared between the oligarchs Len Blavatnik, Viktor Vekselberg and Mikhail Fridman. About 5% of the shares trade on the Russian stock market.

Executives at TNK-BP claim that Tetlis only acquired a minority holding worth about $40,000 one week before the action was raised.

Tetlis is run by former employees of Fridman’s Alfa Bank. Sources close to Fridman deny any further link between the two companies.

Sources close to BP have suggested that tensions are mounting between BP and its Russian partners. TNK-BP now accounts for about 25% of BP’s revenues, about 14% of its profits and about 25% of its reserves.

Tony Hayward, the BP chief executive, is believed to be flying to Russia in the next few weeks for a meeting with his Russian partners.

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