The pair both shook hands with Chinese President Xi Jinping upon arrival and photos show the Kiwis with spots near Indonesian President Prabowo Subianto and Australia's Bob Carr.
But their attendance has been criticised as sending the wrong message by University of Canterbury professor in Chinese politics Anne-Marie Brady, a noted critic of the Chinese government, in a column on the Newsroom website.
Brady said the event was framed as a celebration of China's role in defeating fascism but the attendance of Putin and Kim alongside leaders of other authoritarian regimes signalled it was meant as an "affirmation of a China-centred authoritarian axis".
She said Clark and Key's attendance risked validating a world view at odds with New Zealand's.
"I think engagement with China as our major trade partner is very important, while obviously acknowledging that we have significant differences in political systems."
Millions of Chinese people were killed during a prolonged war with imperial Japan in the 1930s and 40s, which became part of a global conflict following Tokyo's attack on Pearl Harbour in 1941.
Leaders were arriving on Wednesday ahead of the massive parade to cap a week of diplomatic grandstanding by Chinese President Xi Jinping and his allies against the West.
In unprecedented scenes, Xi shook both Putin and Kim's hands and chatted with the pair as the trio walked down a red carpet toward Tiananmen Square.
China will showcase its military prowess with troops marching in formation, flypasts and displays of high-tech fighting gear at the showpiece extravaganza to mark the eight decades since the end of World War 2.
Meanwhile, AFP reported all eyes would be on how the trio of Xi, Putin and Kim - who rarely leaves North Korea - interact with each other in a highly choreographed photo opportunity seen as a coup for China on the world stage.
