Japan's Sumitomo Group has signed on to help the Vietnamese government develop "the most modern smart city of Southeast Asia."

The $4 billion smart city, called the Nhat Tan-Noi Bai project, will lie in the north of Hanoi and feature an international financial centre, ASEAN village, a culture and business fair centre as well as an exhibition centre, Viet Nam News reported.

The project will encompass three sections occupying the length of 11.1km, along the sides of the Vo Nguyen Giap Road, according to the Hanoitimes.

In April, Vietnamese investor BRG Group signed a deal with Sumitomo to develop the project. This was followed by another cooperation agreement between Sumitomo, the BRG Group and the Hanoi People's Committee for the development of the smart city project.

Meanwhile, two Japanese expressway companies have also agreed to assist Vietnam's transport infrastructure projects.

The East Nippon Expressway Company (NEXCO) and Expressway International (JEXWAY) signed a cooperation agreement with Vietnam's Foundation Engineering and Underground Construction Joint Stock Company (FECON) to "transfer their technology and management capacity in transport infrastructure" as part of the transport infrastructure projects in Vietnam.

Under the agreement, the two Japanese companies will buy 20% stake in FECON's build-operate-transfer project, which includes a bypass road in the town of Phu Ly and reinforcement works in the northern province of Ha Nam.

NEXCO and JEXWAY have also agreed to connect FECON with other Japanese investors and partners, according to Vietnamese news outlets.