(Adds context, background, no comment from government, company)
April 5 (Reuters) - Kazakhstan has filed a $1.6 billionclaim against a group led by BG Group Plc and Eni SpA which is developing the Karachaganak gas condensate field,Russia's Lukoil, also a consortium member, said.
The move is the latest sign of tensions between globalenergy majors and national companies in resource-rich nations aslow oil prices put more strain on state budgets which haveballooned over the past decade.
The dispute relates to a formula which determines how profitfrom the development is split between the companies and thegovernment, Lukoil said in its financial report published onMonday, noting the parties were in talks on a possiblesettlement and it did not believe any settlement would have amaterial adverse effect on its finances.
It did not say when Kazakhstan had filed the lawsuit, whenit expected a settlement to be reached and what the likely costimplications would be.
An Eni executive had said in October there were talks onaudit and cost recovery with Kazakhstan over the Karachaganakfield, describing the discussions as normal in such adevelopment.
Kazakhstan's Energy Ministry and Karachaganak PetroleumOperating, a joint venture which runs the project, had noimmediate comment on Tuesday.
Eni and BG, recently acquired by Royal Dutch Shell Plc, each own 29.25 percent of the Karachaganak project innorthwest Kazakhstan, which they jointly operate. State-ownedKazMunayGaz owns 10 percent, Chevron Corp 18percent and Lukoil 13.5 percent.
The Kazakh government said this year the consortium wouldstart an expansion project in 2017 that will cost $12 billion.In 2015, the field produced 141.7 million barrels of oilequivalent in the form of gas and liquids.
Oil is Kazakhstan's main export and a key source of budgetrevenue. The decline of its price has prompted Kazakhstan tostop pegging its tenge currency to the dollar last Augustand let it lose almost half of its value against the greenback.
It has also strained Astana's relations with foreigninvestors. In another recent case, KazMunayGaz representativeson the board of its listed upstream subsidiary clashed withindependent directors over the 2015 dividend. The board voted topay none, against independent directors' proposals. (Reporting by Olzhas Auyezov; Additional reporting by MariyaGordeyeva in Almaty and Raushan Nurshayeva in Astana; Editing byDavid Holmes and David Evans)