The directive covers anyone who has been in Victoria since July 8 and comes into force from 11.59pm on Friday.

Tasmanian Premier Peter Gutwein said the order was expected to last five days and was made out of an "abundance of caution".

"What we're seeing in Victoria at the moment is a very rapid escalation in the number of exposure sites," he told reporters.

"We only need to look how quickly this latest outbreak has spread to realise the risk that it does pose. Now is not the time to become complacent."

Tasmania had already put up a hard border with Victoria from midnight on Thursday, which means only essential travellers are allowed to enter.

Mr Gutwein said about 15,000 people had arrived in Tasmania from Victoria since July 8.

Deputy Director of Public Health Scott McKeown said there was likely a small number of people in Tasmania who had visited Victorian exposure sites but were yet to be identified by contact tracers.

He urged recent Victoria arrivals to limit unnecessary trips, avoid having visitors and to monitor themselves closely for symptoms.

"There are people within our community who have been contacts of cases. There may be a case in the community that we are yet to identify," he said.

Victoria recorded 10 new COVID-19 cases on Friday, the first day of a statewide five-day lockdown, taking the outbreak to 24 cases.

"We are going through one of the largest periods of threat from COVID because of outbreaks on the mainland, particularly the Delta strain," Dr McKeown said.

Tasmania has no recorded cases of coronavirus in the community.

Australian Associated Press