The sister of former Don Dale detainee Dylan Voller has defended him against comments made by former Coalition MP Natasha Griggs.

The former MP said last week that the public should stop treating the teen inmate as a ‘martyr’.

Ms Griggs wrote on Facebook that she was ‘shocked to see Voller dressed in a suit and looking angelic as he gave evidence’.

Voller was giving evidence to the Royal Commission on the treatment he had received during time spent in the Northern Territory’s youth detention facilities.

Speaking to ABC Alice Springs, Kirra Voller says Dylan made no attempt to downplay his crimes.