"I would encourage others to join me on this trip to celebrate the significant historical ties between our two cities."
Mr McDouall honoured and acknowledged the contribution of all those who have supported the relationship in the past 30 years, including the late Tomonobu Nakamura OBE, a Nagaizumi businessman and Rotarian, who encouraged honey exports and funded many exchanges.
The relationship has been marked with an official visit every decade.
A Whanganui delegation attended the 10th anniversary celebrations in Nagaizumi in 1998 and a smaller group visited Japan in 2008 to mark the 20th anniversary.
A 50-strong group from Nagaizumi is expected to attend next February's 30th anniversary of the New Zealand Masters Games in Whanganui.
School parties from both cities have also regularly participated in exchange visits.
Last year a group of Nagaizumi students was hosted in Whanganui by Rutherford Intermediate School.
The students attended class, visited marae, experienced a hangi and also visited tourist attractions.
An opportunity to join Mr McDouall, on a self-funded basis, will be available.
If you would like to attend the celebrations you can register your interest at whanganui.govt.nz before Thursday April 26.
The visit to Japan, from August 2 to 7, will include the official celebration, town tours and meetings with Nagaizumi officials.