Two Australian rowing officials were robbed at knifepoint last night following the Olympic opening ceremony.

The pair were returning to their accommodation in Ipanema, in the city's south, at around 8.30pm when they were approached by two Brazilian youths and robbed at knifepoint.

"They were violently assaulted and robbed," Greg Nance, deputy director of welfare and security for the Australian team said.

"They were shaken up and both of them were shirt fronted, physically handled and thrown against a wall. Both coaches were unharmed."

The thieves reportedly made off with credit cards, mobile phones and a team blazer.

In response, the Australian Olympic committee was taking extra security measures.

Team members are being asked to wear casual clothes, keep accreditation hidden and to avoid walking around after 6pm.