Background <p>Dengue is not endemic in Australia and outbreaks occur occasionally after viraemic travellers visit parts of Queensland where dengue vectors are prevalent. Prior to 2016, <i>Aedes aegypti</i> was the primary vector of dengue in Australia. However, several dengue outbreaks have occurred more recently on islands in the Torres Strait region where <i>Ae. aegypti</i> has been displaced by <i>Aedes albopictus</i> following its first detection in the islands in 2005.</p> Methods <p>In November 2024, adult female <i>Ae. albopictus</i> were collected during a dengue outbreak on Masig Island where <i>Ae. aegypti</i> is now absent after displacement by <i>Ae. albopictus.</i> Collected mosquitoes were pooled and screened for the presence of dengue virus by qRT-PCR and direct RNA sequencing.</p> Results <p>Dengue virus RNA was detected by qRT-PCR in 9 of 12 mosquito pools. RNA sequencing of three positive pools confirmed the virus as belonging to dengue serotype 3 (DENV-3), consistent with the clinical serotype identified during the 2024 outbreak. Sequencing further detected four insect-specific viruses, including Bio Sioux River virus, reported in Australia for the first time.</p> Conclusions <p>These results represent the first detection and whole genome sequencing of dengue virus in <i>Ae. albopictus</i> collected in Australia. The detection of DENV-3 RNA in <i>Ae. albopictus</i> during a concurrent outbreak of the same serotype in the absence of <i>Ae. aegypti</i> supports the ability of <i>Ae. albopictus</i> to drive independent dengue outbreaks. The findings confirm the risk of dengue outbreaks in mainland Australia if <i>Ae. albopictus</i> were to invade and expand beyond its current distribution in the Torres Strait.</p> Graphical abstract <p></p>