"Phelps in breaststroke? That would be the last thing I'd like to see," said Kitajima, who won the breaststroke "double-double" in winning the 100 and 200 event for a second successive Olympics.

"I really hope not to see that happening," he added.

After winning a record eight gold medals last week in freestyle, butterfly, individual medley and relays, the American said he planned to take up new events.

Breaststroke, however, is his weakest discipline and he is pondering taking up backstroke events and the 100 freestyle.

Kitajima, who is considering retiring from the sport, said he was in awe of what Phelps had done in Beijing.

"His achievements are just beyond description, and the whole world recognises his ability," added Kitajima, who also won a bronze medal in the 4x100 medley relay.

"I have great respect for him. We are both athletes, but I'm also a fan of his.