ASTANA, May 28 (Reuters) - Maintenance at Kazakh giant Kashagan oilfield hasn't started yet and shareholders are continuing discussions, Energy Minister Erlan Akkenzhenov told reporters.

According to sources, maintenance at the Kashagan field, which has capacity of about 0.4 million barrels per day, is set to start in early June and may last more than 30 days, reducing Kazakhstan’s overall oil output and exports.