"Make no mistake,if there is widespread community transmission,we may have to introduce some harder measures,"he said.

The nation's top medical experts continue to recommend that it was safe for children to go to school,as Mr Morrison announced he would meet with teachers union representatives on Wednesday.

He said the new measures reflected the size of the issue the government faced to limit its health impacts across the country and to ensure that it could protect the lives of Australians.

He acknowledged the new strict rules placed on weddings and funerals"will be very difficult".

Under the new rules,only five people can attend wedding ceremonies - the couple,the celebrant and witnesses.

Funerals will only be able to be held in the presence of up to 10 people,who must observe the rules around the four-square metre rule and the social distancing practices. The same 10-person limit will apply to any gatherings inside people's homes.

"This is not an easy decision,"Mr Morrison said."Some of the events that have been some of the major transmitting events,it has been exactly these types of events,particularly weddings.

"And that is why,regretfully,we have to be able to put these arrangements in place."

Hairdressers and barber shops will be able to stay open but have been ordered to strictly manage social distancing,limit the number of people in their premises and restrict the amount of time a patron is in the premises to no more than 30 minutes.

Mr Morrison said every worker in Australia would be listed as"essential".

"Everyone who has a job in this economy is an essential worker. Every single job that is being done in our economy with these severe restrictions that are taking place is essential,"he said.

"It can be essential in a service whether it's a nurse or a doctor or a schoolteacher,or a public servant who is working tonight to ensure that we can get even greater capacity in our Centrelink offices,working until 8 o'clock under the new arrangement in the call centres,these are all essential jobs.

"People stacking shelves,that is essential. People earning money in their family when another member of their family may have lost their job and can no longer earn,that's an essential job. Jobs are essential."

He also flagged state and territory governments were working to provide relief to people who will not be able to pay their rent and discussions were taking place with energy companies to ensure power supplies were not cut to homes who could not pay their bills on time.

Australian citizens and residents profiteering by sending essential supplies,such as masks and baby formula,to overseas markets will also face prosecution in a new crackdown to shore up domestic goods and services.

Mr Morrison said 2020 would be the"toughest year"of many people's lives. Australians had already lost work or been forced to close their businesses in one of the most"heart-breaking events"in the nation's history,he said.

He said the national cabinet,which includes state and territory leaders,was working hard to address the many issues Australians were facing.

"We are not unconscious of the real impact these measures are having on the lives of daily Australians so we will continue to do everything we can,"he said.

Mr Morrison said if Australians followed the advice,then a full lockdown could be avoided,but warned that if the measures were not taken seriously and the infection rate kept rising then more restrictions were inevitable.

"We know it is a massive change to our lives but if we do it,and we do it consistently,and we do it patiently and understandingly,then we will get through this,"he said.