A case of racial abuse toward South African coach Paul Treu by South Africans is under investigation.
It was confirmed on Tuesday that Treu was racially abused after his team lost to Samoa in the semifinals on Sunday.
Treu confirmed the incident to SA Rugby, which has started an investigation.
"We abhor racism of any kind," SA Rugby said. "This is especially so in the light of our efforts as South Africans to build a nonracial society that respects all the citizens of the country.
"We wish to make it clear that Paul Treu and his team are bona fide representatives of South Africa, and that they uphold the nonracial values of South Africa. They should, therefore, be protected from any form of abuse.
"We view the Hong Kong incident in a serious light and we will take appropriate action upon conclusion of the investigation."
Media reports said the South African fans were angry that there was only one white player in the starting lineup for the semifinal, and shouted insults at Treu during a postmatch interview on the sideline. They then spat at Treu as walked under the stand.
Samoa won 10-0 and went on to defeat Fiji in the final.