The latest telephone survey jointly conducted over the weekend by Nikkei Inc. and TV Tokyo Corp., revealed the cabinet's approval rating had slumped for the first time in four months as Kan faces growing pressure from within his own and opposition parties to step down as prime minister at a clearly defined time.

Kan survived a no-confidence motion brought against him by opposition parties on June 2, by saying he will step down when reconstruction efforts following the March 11 twin disasters have swung into full gear.

However, having secured a 70-day extension of the current Diet session to try and secure passage of a second disaster-related budget through a divided parliament, the embattled prime minister has suggested that he wants to cling on to his position for as long as possible and has hinted he also wants to try and stay on to push a third extra budget through parliament.

The telephone poll conducted from June 24 to 26, with 893 providing valid responses from a sample of 1,501 households, also showed that the disapproval rating for Kan's cabinet rose 3 points to 65 percent.

According to the latest poll, 42 percent of those surveyed said they wanted the prime minister to leave office of his own volition and be replaced immediately.

Meanwhile, 69 percent of those asked replied they were circumspect about the firing up of idle nuclear reactors in Japan following a period of mandatory suspension for spot safety checks.

The public were of the opinion that the safety measures taken to ensure nuclear power plants in Japan won't experience the same monumental failures that led to the Fukushima nuclear crisis, the worst since the 1986 Chernobyl disaster, were woefully insufficient, the Nikkei reported.

Kan's approval rating hit an all-time low of 19 percent in February according to a survey taken by the popular daily the Mainichi Shimbun, prior to Kan's perceived mishandling of the march 11 earthquake, tsunami and following Fukushima nuclear crisis.

The prime minister, Japan's fifth in as many years, succeeded former prime minister Yukio Hatoyama, who stepped down after his support rate plummeted to 20 percent, following his botched handling of an agreement to relocate a controversial US military base within Okinawa prefecture.