Royal Dutch Shell Plc (NYSE: RDS.A) sold its stake in a New Zealand gas field while taking over the field's operating company as part of a plan to possibly divest its holdings in the country later on, the company said April 6.

Shell has sold its 50% stake in the Kapuni Gas Field, New Zealand's second-largest, for an undisclosed price and has increased its holding to 100% in the joint venture that operates the field, Shell Todd Oil Services (STOS), it said in a statement.

The announcement was the first concrete action taken by Shell following its report in 2015 that it was reviewing its New Zealand business interests.

"This 100% ownership of STOS will simplify Shell's operational structure in preparation for any possible portfolio changes to the remaining assets," Rob Jager, country chair of Shell New Zealand, told Fairfax Media.

Shell, which has operated in New Zealand for more than a century, said in December 2015 it was reviewing its business interests in the Pacific nation as the company seeks to streamline its global portfolio amid a slump in energy prices.