Nguyen Thi Nhung, vice president of the Vietnam Shooting Federation and the head coach of the national team, said Tran Quoc Cuong too might skip the biennial games to be held in Hanoi in late 2021.
The 45-year-olds are focusing on qualifying for the Olympics, with qualifiers set to be held in the upcoming months.
"Despite being the reigning champion I cannot be sure about what could happen because the Olympics is a really competitive event with the participation of all the best shooters in the world," Vinh told Vietnam News Agency.
At the 2016 Olympics in Rio de Janeiro, Brazil, Vinh won a gold and a silver medal each in the men’s 10-meter and 50-meter air pistol events, while Cuong did not win any medal.
Vietnam has done well in SEA Games shooting. Both marksmen won four gold medals in the 28th Games and one more two years later.
Last year in the Philippines both failed to win golds, with Vinh winning just one silver medal after losing to Thailand's Pongpol Kulchairattana.
Nhung said Vietnam depended too much on the veteran shooters and is trying to develop the next generation of elite shooters.
"The best of them will be selected through national championships and trained with the national team. However it will be a long process. I think we will have to wait from at least six to eight years to have one reach the international level and get a result in the Olympics."