Japanese Second World War leader Hideki Tojo wanted to keep fighting even after US atomic bombs destroyed Hiroshima and Nagasaki, accusing surrender proponents of being "frightened," a newly released diary reveals.

Excerpts from the approximately 20 pages written by Tojo in the final days of the war and held by the National Archives of Japan were published for the first time in several newspapers yesterday.

"The notes show Tojo kept his dyed-in-the-wool militarist mentality until the very end," said Kazufumi Takayama, the archives curator. "They are extremely valuable."

Tojo, executed in 1948 after being convicted of war crimes by the Allies, was prime minister during much of the war. The notes buttress evidence that Tojo was fiercely opposed to surrender.

"We now have to see our country surrender to the enemy without demonstrating our power up to 120%," Tojo wrote on August 13, 1945, two days before Japan gave up.

Tojo criticised his colleagues, accusing government leaders of "being scared of enemy threats and easily throwing their hands up". Surrender proponents were "frightened by the new type of bomb' and terrified by the Soviet Union's entry into the war," he wrote.

The writing is remarkable considering it was penned days after the US atomic bombs incinerated Hiroshima and Nagasaki, killing 200,000 people and posing the threat of the destruction of Japan.

The notes first came to the notice of the government when Tojo's defence lawyer, Ichiro Kiyose, gave them to the Justice Ministry. They were made available to researchers last year.

On August 10, 1945, Tojo claimed the purpose of the war was to "maintain stability in East Asia and defend our country."

On August 14, 1945, the day before Japan surrendered, Tojo wrote in a note addressed to a former aide that he took "moral responsibility for causing useless deaths, even though they were meant to be sacrifice for a great cause".

"I am determined to offer an apology with my death," he wrote.