By Agence France-Presse
Abe sent a sacred "masakaki" tree bearing his name to the shrine as it started a three-day spring festival, a shrine spokeswoman said.
On the eve of the festival, more than 70 lawmakers made a pilgrimage to the shrine, which China and South Korea see as a symbol of Tokyo's past aggression.
Kyodo News and other reports said Abe would not visit the shrine during the festival to avoid creating tension as he plans to host a trilateral meeting with Chinese Premier Li Keqiang and South Korean President Moon Jae-in in early May.
The conservative premier, who has been criticised for what some see as a revisionist attitude to Japan's wartime record, has sent ritual offerings to mark the shrine's key events, including its commemoration of the end of World War II.
The shrine honours millions of Japanese war dead, but also senior military and political figures convicted of war crimes after World War II.
The site has for decades been a flashpoint for criticism by countries that suffered from Japan's colonialism and aggression in the first half of the 20th century.
Abe visited in December 2013 to mark his first year in power, a move that sparked fury in Beijing and Seoul and earned a diplomatic rebuke from close ally the United States, which said it was "disappointed" by the action. He has since refrained from going.
Abe and other nationalists say Yasukuni is merely a place to remember fallen soldiers, and compare it with Arlington National Cemetery in the United States.
Tokyo is also seeking warmer ties with Beijing and Seoul, key countries in dealing with the unpredictable North Korean regime.