Police have admitted security lapses over Friday's assassination of the former PM, which came two days before Japan held a vote for the upper house in parliament.
Japan went to the polls on Sunday in the shadow of the assassination of former Prime Minister Shinzo Abe, who was gunned down while making a campaign speech on Friday.
Prime Minister Fumio Kishida led a minute's silence for Abe at the headquarters of the governing Liberal Democratic Party (LDP) before announcing winning candidates.
Exit polls for the election for the parliament's upper house showed Abe's governing party certain to win a major victory, possibly propelled by what is seen as a wave of sympathy votes in a country still reeling from the shock of Friday's brazen shooting.
Projections by the public broadcaster NHK suggest the LDP and its ally Komeito could together win up to 83 of the 125 seats up for grabs on Sunday. The Senate has a total of 248 seats, renewed by half every three years.
In the wake of Abe’s assassination, Sunday’s election had a new meaning, with all political leaders emphasising the importance of free speech and their pledge not to back down on violence against democracy.
Also on Sunday, police in western Japan sent the alleged assassin to a local prosecutors' office for further investigation. He had been detained at a police station for two days.
Police say the 41 year old suspect said he had believed rumours that Abe was connected to a religious organisation that caused his family financial problems.
He also told investigators he had attempted to make a bomb, police said. Meanwhile a handmade gun found at the scene was one of several confiscated from his apartment.
But Abe's death has raised security questions. A top police official has admitted that possible security lapses allowed the assassin to get in close range of the prime minister in broad daylight.
"I believe it is undeniable that there were problems with the guarding and safety measures. The urgent matter is for us to conduct a thorough investigation to clarify what happened," said Tomoaki Onizuka, head of the Nara prefectural police.
The veteran politician has been praised by mourners and leaders for his knowledge and experience in international politics and for preventing the deterioration of US-Japanese relations.
Current Japanese Prime Minister Fumio Kishida who leads the conservative party denounced the "barbaric" attack on his former mentor, insisting on the importance of "defending free and fair elections".