AUSTRALIA has approved the controversial appointment of a former naval commander as Sri Lanka's high commissioner, prompting Australia's Tamil community to accuse the government of protecting a war criminal.

Retired Admiral Thisara Samarasinghe was appointed as high commissioner to Australia on Friday.

Since learning of his nomination for the role earlier this year, Australia's Tamil community has lobbied the Gillard government to reject Admiral Samarasinghe in response to Sri Lanka's refusal to allow an international war crimes tribunal.

Australian Tamil Congress spokeswoman Sam Pari said the Tamil community felt betrayed and disappointed as the appointment would give an accused war criminal diplomatic immunity.

Admiral Samarasinghe became Sri Lanka's navy commander after the 26-year war against the Tamil Tigers ended in 2009.