A Bangladeshi government minister said last week that the oil and gas firm had "mistakenly" been given permission to carry out a survey on St Martin's coral island and that it should now suspend seismic work for a 10km radius surrounding it.

The company began a $7m ( 5.7m) seismic survey of exploration blocks close to the island last month after obtaining clearance to do so last December. Tullow chief executive Aidan Heavey told the Sunday Tribune in January that the area had shown promise in the past in terms of potential reserves.

The government is to review an environmental impact report before making a final decision regarding St Martin's, which is home to nesting sites for turtles.

Earlier this year French oil giant Total acquired a 60% stake in two offshore blocks in Bangladesh that were majority-owned by Tullow. Total will spend $20m to conduct surveys of the blocks.

Tullow Oil's major gas play in Bangladesh is onshore, in an area surrounding the capital, Dhaka.

Bangladesh is thought to have existing recoverable gas reserves of 13 trillion cubic feet.