Tullow Oil, the Africa-focused energy group, said on Monday it would review its 2015 production forecast after technical issues at its key Jubilee field in Ghana caused the suspension of gas exports and constrained oil output.

Tullow said on Monday that gas export from Jubilee to the Ghana Gas plant at Atuabo has been suspended since July 3 due to technical issues and is not expected to resume until mid-August.

The firm said oil production is currently constrained to approximately 65,000 barrels of oil per day, and as a result it will review its 2015 production forecast for Jubilee and provide an update on progress at its half yearly results on July 29.

Tullow said the issues did not have an effect on the field's reservoir or resources.

Tullow has mobilised a team of experts to rectify the fault within the gas compression system and estimates that it will take approximately a further three weeks to reinstate gas export and full oil production.

Shares in Tullow, down 64 percent over the last year, closed Friday at 282 pence, valuing the business at 2.6 billion pounds.