Tokyo - Japan baked under scorching temperatures for a fourth successive day on Tuesday, as the capital's heat broke nearly 150-year-old records for June and authorities warned power supply remained tight enough to raise the spectre of cuts.

Temperatures in the capital hit 35.1 C by 1 p.m local time on Tuesday (0400 GMT), after three successive days of temperatures topping 35 C - the worst streak of hot weather in June since records began in 1875. And the heatwave isn't about to break: the Japan Meteorological Agency forecast highs of 36 C for Tokyo on Thursday and 35 C on Friday.

The heatwave comes less than two weeks before a national election in which prices, including the cost of electricity, are among key issues picked by voters in opinion polls that show the government's approval rating slipping - with politicians including Tokyo's governor urging power price cuts.

For a second day, authorities asked consumers in the Tokyo area to conserve electricity to avoid a looming power cut.

-Reuters