Utility giant Tenaga Nasional said its net profit for the first quarter rose to RM1.514 billion, up 21.6 percent annually on higher electricity sales.

For the three months to November, the state-controlled firm posted revenue of RM6.208 billion against RM5.602 billion in the previous year's quarter.

Net profit was boosted by a foreign exchange gain of RM242.4 million compared to RM186.2 million previously.

Tenaga is Malaysia's fourth-biggest listed firm and the country's largest power utility firm. It generates 55 percent of the total electricity capacity of Peninsular Malaysia's power requirements.

Tenaga said prospects for the full year will be more "challenging" than the previous year due to higher payments to independent power producers to secure electricity.

"For the current year, whilst demand growth may exceed current expectations of 6.0 to 6.5 percent in line with the projected GDP ... rising operating costs caused by external factors will weigh down on operating margins," it said.