NEW DELHI, April 13 (Reuters) - India has asked companies to operate underutilised gas-based power plants in May and June, and extend operations of imported coal-based plants until Oct. 15 to meet anticipated high demand for electricity, according to two government orders.

The South Asian nation registered an 8% rise in electricity consumption in the financial year that ended last month, and demand is expected to rise in the hot summer months.

In an order dated Friday, the government for the first time invoked an emergency clause mandating companies to operate underutilised gas-based power plants by importing the fuel.

India has about 24 gigawatts of gas-based power plants that have been idling or underused for decades due to lack of fuel. Power stations will be informed two weeks in advance about the requirements so they can import gas, the order says.

"Gas-based power plants are required to meet the anticipated surge in power consumption in summer months," the order says.

Torrent and NTPC are among the big gas-based power station companies.

In another order, seen by Reuters on Saturday, the government invoked an emergency clause directing companies such as Tata Power and Adani Power - which are operating imported coal-fired plants with a capacity of nearly 16 gigawatts - to continue operations.

The plants were initially allowed to operate until June 30. (Reporting by Sarita Chaganti Singh; Editing by William Mallard)