NSMO forecasts a heatwave between June 21 and 26, with temperatures in Hanoi and northern Vietnam reaching up to 39 degrees Celcius and perceived temperatures in urban areas climbing to 45 degrees Celcius.
NSMO warned that the prolonged heatwave could trigger a sharp increase in electricity demand, particularly during afternoon and evening peak hours.
To prepare for the surge, the operator said it was closely monitoring weather conditions and had implemented a range of measures to strengthen system reliability.
Hydropower plants are managing water resources to maximise peak-hour generation, while coal-fired plants are reviewing operations and maintenance schedules to ensure availability.
Gas-fired, LNG and oil-fired power plants have also secured fuel supplies and are ready to increase output if demand rises sharply.
Meanwhile, operators are stepping up monitoring of transmission and distribution networks to maintain system reliability and minimise the risk of disruptions.
During a previous heatwave in late May, Vietnam's peak electricity demand reached 58,103 MW, while northern Vietnam recorded a peak load of 29,966 MW.
NSMO urged households, businesses and public agencies to use electricity efficiently and avoid operating multiple high-power appliances simultaneously during peak hours between 5.30 pm and 10.30 pm.