Premier Gladys Berejiklian has appointed top Sydney silk Bret Walker SC as commissioner for the inquiry, which will report back to the government in three to four months.

Eighteen of Australia’s 62 deaths and more than 700 cases have been linked to the Ruby Princess.

According to a statement from Berejiklian’s office, Walker has been given the “extraordinary powers of a special commissioner to examine all matters involving the cruise ship, including its departure and arrival, and the actions of all agencies and parties involved”.

NSW Police and the State Coroner will continue their investigations into the incident.

NSW Police Commissioner Mick Fuller on Tuesday said his investigation would likely take six months to carry out.

“It is important that answers are provided quickly for the people of NSW,” Berejiklian said.

“As I have said before, we will leave no stone unturned until we find out exactly what happened.”

Comm. Fuller this morning said the Ruby Princess should depart Australia by the end of the week.

“In terms of the Ruby update, we are working with Carnival Cruises and Border Force and NSW Health and looking for a hopeful departure date of this Sunday,” he said.

NSW has reported 16 new cases overnight but testing for coronavirus in the state has dropped significantly.

“It’s with a degree of caution that we welcome that low number of new cases,” Berejiklian said.

Around 1300 tests were carried out on Tuesday, down from a peak last week of 4500 tests in one day.

The Premier urged anyone living in the 12 areas which have been pinpointed as troublesome community transmission hotspots to get tested if they have even mild symptoms of the virus.