The two leaders discussed ways to deepen the Comprehensive Strategic Partnership established in 2023, focusing on energy, critical minerals, artificial intelligence, semiconductors and space.
"The two sides identified economic security as a new priority area for bilateral cooperation," Takaichi told reporters after the meeting on Saturday.
"With regard to critical minerals... both sides agreed to strengthen close coordination to ensure stable supplies and reinforce supply chains.
In a joint move, Vietnam and Japan signed six agreements encompassing infrastructure, climate action, agriculture, technology, digitalisation, and space cooperation.
Japan remains one of Vietnam's largest foreign investors, with many Japanese multinationals operating large manufacturing facilities in the country.
Vietnam has been seeking support from Japan and other countries for oil supplies as conflict in the Middle East drives prices higher and disrupts supply chains.
Under the $US10 billion Power Asia Initiative to support Asian countries' energy self-reliance, Japan will assist in arranging crude oil supplies for Vietnam's Nghi Son Refinery and Petrochemical Complex, Hung said.
Takaichi was also set to meet Vietnam's Party Secretary and President To Lam on Saturday afternoon and deliver a keynote speech at Vietnam National University, marking a decade since former prime minister Shinzo Abe introduced Japan's "Free and Open Indo-Pacific" strategy.
Her address is expected to emphasise autonomy and resilience for regional nations.