"We can't afford that because if people behave like that, then we lose lives," he told 2GB radio on Friday.
"Honestly I think it was still an indication that people just weren't getting it."
The prime minister issued a warning for travellers ignoring advice.
"Those who go overseas over this period, how they actually think they're going to get back now is going to be very difficult," he said.
"I don't think they'll find themselves high on the list."
Mr Morrison said there were some exceptions among the 16,000 for people travelling for aid and scientific work.
People in Australia must stay at least 1.5 metres away from others and gatherings are limited to two people unless you are with your family or household.
If you believe you may have contracted the virus, call your doctor (don’t visit) or contact the national Coronavirus Health Information Hotline on 1800 020 080. If you are struggling to breathe or experiencing a medical emergency, call 000.
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