Construction of the HTW5.0-126 will finish by the end of March and testing is due to start by the end of September.
The new turbine combines a medium-speed generator with permanent magnet drive and features a rotor diameter of 126 metres.
The downwind model has been designed for typhoon-prone IEC-Class S (annual average wind speeds of 10m/s) enabling it to withstand wind conditions typical in that region.
Hitachi said the turbine could be mounted on floating platforms. The Japanese company is already providing a 2MW turbine for the Fukushima floating offshore project, which started generating electricity in October.
Hitachi plans to start selling the HTW5.0-126 by March 2016.
In July 2012 Hitachi announced plans to build the 5MW turbine, a scaled-up version of the 2MW design the company acquired when it bought Fuji Heavy Industries' wind division turbine division in the same month.