The duo failed to clear the qualifying rounds at the Japan Open in Tokyo yesterday.
Chun Seang, who is expected to feature as the second-ranked singles player for Malaysia in the Korat SEA Games in December, was beaten 20-22, 18-21 by Japan's former Asian junior champion Kenichi Tago in the second round of the qualifiers.
Chun Seang, who is the top junior player from the 2010-2012 Project squad under Rashid Sidek, had earlier beaten Japanese Koichi Saeki 21-9, 21-16 in the opening match.
Kwong Beng, another SEA Games hopeful, went down 11-21, 21-14, 19-21 to South Korea's Lee Cheol-ho after fighting for 50 minutes in the first round.
Malaysian veteran Pei Wei Chung also failed to make it to the main draw. He lost his opening match 21-15, 14-21, 13-21 to Taiwan's Liao Sheng-shiun.
Only Chun Seang and Kuan Beng Hong have been named as the singles players in the national squad for the SEA Games so far. The Badminton Association of Malaysia (BAM) are sending the second stringers to the Games this time.
Chun Seang and Kwong Beng will compete in the Taiwan Open next week.