"As president of the organising committee, I would like to express the hope of 1.5 million citizens from Gwangju," the city's mayor, Lee Yong-sup, told reporters on Thursday.
"They're sincerely expecting North Korea's participation ... North Korea's presence is crucial for the success of this event as the motto of the competition is 'Dive into Peace'.
"We would like to emphasise this message to the world. Last February, ministers from the two countries met with the IOC (International Olympic Committee) in Lausanne and this issue was discussed, but so far we have no answer from the North Korean side."
FINA executive director Cornel Marculescu said correspondence was being exchanged in the hope of securing North Korea's presence. The registration deadline is June 12.
"This is an ongoing process, and we are confident that over 190 nations will be present in Gwangju," Marculescu said.
Sports diplomacy has been a prominent feature of the thaw in relations between the Koreas since early 2018, when they fielded a unified women's ice hockey team at the Winter Olympics in Pyeongchang, South Korea, and marched under a unified flag.
The two countries agreed to field joint teams in various sports in February and have also expressed interest in jointly hosting the 2023 women's soccer World Cup.
However, the rocket drill brought talks about sports and other inter-Korean exchanges to a halt.
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Kevin Liffey)
