By Alan Baldwin

RIO DE JANEIRO (Reuters) - South Korea's top swimmer Park Tae-hwan apologized to his compatriots after bombing out of another race at the Rio Olympics on Sunday.

"I was afraid of looking up at the scoreboard," he told the Yonhap news agency after finishing last in his 200 meters freestyle heat.

"I didn't want to come out of the pool."

Park's presence in Rio has been controversial, the country's first Olympic swimming medalist winning a late battle to compete after appealing against a doping ban.

The 2008 gold medalist in 400m freestyle failed to qualify for the finals in that event on Saturday after clocking the 10th-fastest time.

On Sunday he was 29th overall in the 200m, a time 2.31 seconds slower than Chinese pacesetter Sun Yang, ending his hopes of winning a medal in the distance for the third Games in a row after silvers in 2008 and 2012.

Park completed an 18-month ban imposed by world governing body FINA in March after testing positive for testosterone ahead of the 2014 Asian Games.

Under a controversial Korean Olympic Committee regulation, he was then hit with an additional three-year ban from the national team the day the FINA suspension expired.

That would have ruled him out of contention for Rio but the Court of Arbitration for Sport cleared the 26-year-old to compete. He is also due to swim in the 100m and 1,500m freestyle races in Rio.

"I wanted to put yesterday's 400m race behind me," he said on Sunday. "But I think I was trying too hard to make up for it and my shoulders didn't move the way I wanted them to."

(Reporting by Alan Baldwin; Editing by Bill Rigby)