(5 p.m. EDT) -- New Zealand Prime Minister Jacinda Ardern has poured cold water over the idea of a Trans-Tasman travel "bubble" between New Zealand and Australia, according to reports in the
.While New Zealand has managed to go over three months without a case of COVID-19 with no known source, the Australian city of Melbourne saw 760 active cases of COVID-19 with no known source on Sunday, according to the Herald.Those increasing numbers have led Australia's second-largest city to impose lockdown restrictions for six weeks, with a curfew in effect from 8 p.m. until 5 a.m. daily, lasting until September 13.In response to the outbreak, Australia has also tightened restrictions for the state of Victoria, where restaurants, cafes, bars and gyms will close once again beginning at 11:59 p.m. on Wednesday.These increased cases prompted New Zealand's Prime Minister Ardern to state that no Trans-Tasman bubble will be in place until Australia was free of community-transmitted COVID-19 cases for at least 28 days.Initially, the concept of a safe corridor, or travel bubble, between the two countries was encouraging. Air New Zealand had scheduled a flight between Canberra and Wellington on July 1, and local cruise operators in Australia prepared to restart.The return of COVID-19 to Australia has pushed those plans back, however. Regardless of size, most cruise lines in Australia do not plan to restart operations until the fall at the earliest. The return of the virus has thrown the work done by Australia's Tourism Restart Taskforce out the window.Australia has currently banned cruise ship travel through much of September. Queensland Health has gone one step further stating that foreign-flagged ships will not be allowed in its waters "until the end of the declared public health emergency".