A Melbourne woman who was infected with COVID-19 on a ski holiday in the US attended a 21st birthday party where at least six people have been struck down with the virus.

The outbreak at the party held in Malvern on March 14 are the latest coronavirus cases to be linked to a group of wealthy Australians who attended the exclusive Colorado resort of Aspen, where at least a dozen Australians tested positive.

The rapid spread of the disease has caused ructions among guests at the party, who claim the woman should have immediately placed herself into isolation when she returned to Melbourne on March 13.

Australians were part of a cluster of coronavirus infections in Aspen, Colorado. Credit:The Aspen Times/AP

But the following day, the woman mingled with about 80 guests at the function. The woman, who The Age and the Herald have chosen not to name, had not experienced any symptoms and had not been tested before the function.