The fires, which have claimed the lives of at least six people, may only get worse this week.
Strong winds from those fires were blowing smoke over much of Sydney, leaving the harbour city shrouded in thick smog.
People with respiratory or heart conditions were advised to stay indoors and seek medical advice when necessary.
Morrison said his government was "getting on with the job".
Workers heading into the city and children going to school put on masks to deal with risky air quality, while 55 bushes and grass fires still burned across the state after two weeks. "The dust and smoke is everywhere".
"This is the worst of the weather from a fire behaviour point that we will have seen", Eden told reporters in Adelaide, the state capital.
"The smoke will linger around". Of the blazes burning, 25 of them have yet to be contained. More than 1000 firefighters remain in the field.
Code red is the highest possible rating on the state's fire danger scale, the equivalent to the "catastrophic" fire rating in other states.
On Thursday, it was Victoria's turn, with dozens of fires burning across the state by early afternoon.
The RFS tweeted aerial footage showing smoke billowing into the air from the latter fire, which has now consumed more than 33,000 hectares.
Other "watch and act" alerts are now in place for long-standing fires at Carrai Creek near Walcha and Moonbi near Tamworth.
The teams searched an Indigenous Protected Area, Ngunya Jargoon, near Wardell, which has been ravaged by two fires in the past month.
While there are no total fire bans in place for Saturday, nine regions - including the ACT - were at a "very high" fire danger.
The country is bracing for challenging fire conditions to continue throughout the Southern Hemisphere summer.
But, after a fortnight of serious fires, he's hopeful conditions will soon improve. In the wake of the blazes, several animal-rescue teams have been fanning out to try and find the koalas which could have been injured. The firefighters expect that the fire bushes will continue for weeks without significant rainfall.
The Bureau of Meteorology said "large areas" of central and eastern Victoria broke maximum temperature records for November - including in Melbourne where the mercury reached 40.9 deg C - while a dramatic dust storm swept through the town of Mildura, turning the sky a vivid orange.
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