Israeli Prime Minister Benjamin Netanyahu was discharged from hospital Sunday in "excellent condition", a day after being admitted for dehydration, his office and the hospital said.

The 73-year-old was transferred to the Sheba medical centre near Tel Aviv on Saturday with dizziness after having spent the previous day in the scorching heat of the Sea of Galilee in Israel's north.

By late Sunday morning, Netanyahu had "completed a series of tests and is in excellent condition", said professor Amit Segev, Sheba's head of cardiology.

"Our diagnosis, at the end of all the tests performed, including the laboratory tests, is that the reason for the hospitalisation was dehydration," he said in a video statement.

As part of the cardiological tests, Sheba decided to use "a subcutaneous (implanted) Holter" on Netanyahu to "continue regular monitoring" of his heart, Segev said. 

Shortly after, Netanyahu's office announced the premier had left Sheba hospital.

Netanyahu, who was reelected late last year, heads a hard-right coalition whose proposed judicial overhaul has triggered weekly demonstrations since January.

The premier is also standing trial for corruption charges he denies.

In October, Netanyahu was hospitalised overnight after feeling ill while observing the Jewish fast of Yom Kippur.

In a video message released Saturday from hospital, Netanyahu said he had spent hours outdoors "in the sun, without a hat, without water".

He urged Israelis to "spend less time in the sun" and "drink more water" in the wake of the country's hot weather.