Kazakhstan warned international oil companies at the weekend to stop living "in ancient times" as it prepared to tighten the fiscal regime at oilfields and increase state ownership of its flagship Caspian Sea development.

Daulet Yergozhin, Kazakhstan's deputy finance minister, said, draft revisions to the tax code, to be debated in parliament early next year, would increase budget revenues, be "simple to administer and collect and very understandable for oil and mineral producers".