At least two women rushed into the ring in Maizuru, northwest of Kyoto, after a local mayor collapsed while giving a speech.
But as the women attempted to help the mayor, multiple announcements were made over loudspeakers asking them to leave the ring, city official Noriko Miwa told AFP.
The rings where sumo is practised, known as sumo dohyo, are seen as sacred places in the native Shinto faith.
Women, who are considered to be "ritually unclean", are barred from stepping into them.
According to witnesses cited by local media, sumo officials threw large quantities of salt into the ring after the women had entered, in an apparent bid to "re-purify" the sacred ground.
In a statement, the sumo association's chief, who goes by the name Hakkaku, described the announcements as "inappropriate" under the circumstances.
"The announcement was made by a referee who was upset, but it was an inappropriate act in a situation that involves one's life. We deeply apologise," Hakkaku said.
"We pray from the bottom of our heart for safety of the mayor, and express our deep gratitude towards women who offered emergency measures on the spot," added the sumo chief.
Miwa said the mayor had been hospitalised and was now in a stable condition.
A row erupted in 1990 when then chief cabinet secretary Mayumi Moriyama wanted to present the Prime Minister's Cup to a sumo champion in the ring. She eventually lost that battle in the face of ultra-conservative sumo bosses.
A decade late, Osaka mayor Fusae Ota took up the fight again, trying several times to present the champion's trophy in a tournament held in the city. She too found herself banned from the ring.
Sumo traces its origins back 2,000 years to a time when it was an integral part of Shintoism.
Ritual is a key component of the sport, and sumo wrestlers are expected to adhere to a rigid moral code.
But the sport's stock has fallen in recent years with claims of bout-fixing, illegal betting and bullying, including the violent hazing death of a young apprentice wrestler in 2007.
Sumo is still recovering from a damaging scandal last year when former grand champion Harumafuji was charged over a brutal assault on a rival wrestler while out drinking.
Japanese Twitter commentators were swift to express their outrage, with one user writing under the handle @yoox5135 asking: "So women are unclean? The sumo association should go under. This is so stupid."
Another user, @miroku203, wrote: "If tradition is more cherished than a person on the verge of death who is in front of you, the sumo association should collapse."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)