The fund led by the international federation will finance capital projects such as the rebuilding of the Tonga Rugby Union's offices and high-performance gymnasium as well as the rehabilitation of rugby grounds across Tonga.
In addition to its initial pledge, World Rugby will set-up a process to facilitate donations by member unions, regions, rugby bodies and individuals and empower its global family to support the return of rugby in Tonga.
This second phase of support follows the completion of the initial humanitarian relief, which was generously supported by the global rugby family.
The $195,000 grant will supplement World Rugby's annual funding to support the union, its personnel and high-performance programmes which had been already increased to mitigate the pandemic's impact on unions' finances.
Funds donated by the international federation signal the gradual return of rugby in Tonga, a sport that plays a central part in the daily lives of communities on the islands.
The 'Ikale Tahi, Tonga men's national team, will return to test action in July when they take part in the World Rugby Pacific Nations Cup 2022 before looking to secure their place at Rugby World Cup 2023 via the Asia/Pacific qualifier.
Tonga Rugby Union (TRU) CEO Peter Harding welcomed the news.
"This assistance from World Rugby will help the Tonga Rugby Union to find constructive ways of assisting sport to recover from the volcanic eruption and tsunami.
"The board of the TRU want to thank World Rugby for the generous donation and will use the assistance to recover installations and infrastructure to encourage and improve the services to our players on the island."
Tonga Rugby Infrastructure and Rebuilding Fund Chair, Brett Robinson, said the job is personal.
"Having been fortunate to have close ties to Tonga, and in particular having played with lifelong friends in Toutai Kefu (Souths, Reds and Wallabies) and Ipolito Fenukitau (Brumbies), the importance of supporting the rebuilding of Tongan rugby infrastructure through World Rugby takes on a special meaning for me.
"Tonga is one of world rugby's great rugby nations and it also plays a significant role on the islands for the health and wellbeing of the Tongan community.
"World Rugby, with our global rugby community, was horrified to observe the devastation of the impacts of the tsunami earlier this year, and along with broader humanitarian support that's been provided the rebuilding of rugby infrastructure will be critical in the nation getting back on its feet again."