Japan's government says there will be enough electricity to ensure stable supplies over the coming week, when hotter than average temperatures are forecast in the country.

The Economy, Trade and Industry Ministry on Friday released its nationwide projections of reserve power supply capacity for peak hours in the week from Saturday.

The Tokyo Electric Power Company has a reserve margin of between 6 and 9 percent for weekdays when demand increases.

Tohoku Electric in northeastern Japan has a margin of between 6 and 11 percent, and that of Hokkaido Electric in the north is 7 to 11 percent. Utilities serving other regions have reserve capacities of at least 10 percent.

In July, the government is due to issue a nationwide request for power-saving for the first time in seven years. It says electricity supplies will be tight if temperatures rise to once-in-a-decade levels.

Officials are asking people to switch off unnecessary lights and take other steps within a reasonable range. They say air conditioners should be used appropriately to prevent heatstroke.