Blazes have erupted as temperatures typically seen in summer gripped Queensland’s southeast on the first weekend of spring.

Residents are on high alert with the unseasonably hot start to the season bringing increased fire risks in the nation’s east.

Firefighters told residents at Plainland, west of Ipswich, to prepare to leave on Sunday afternoon due to a dangerous and fast-moving bushfire near the Warrego Highway.

Fire bans were issued in Queensland’s Ipswich and the Lockyer Valley on Sunday.

The NSW Rural Fire Service issued an emergency warning, which was later downgraded, for a large grass fire burning near Tabulam, in the state’s north.

Brisbane reached a high of 34.4 degrees on Sunday, making it the hottest September day in the city since 2019.

“If we get a run of westerlies, potentially we can see some late afternoon heat if those westerlies increase and brings some hotter air out towards Brisbane from inland,” the Bureau of Meteorology’s Steve Hadley said.

Coastal areas from Gladstone to the Gold Coast came a few degrees shy of breaking the record for the state’s highest recorded temperatures for the start of spring.

The state had experienced its third-warmest winter on record with temperatures 1.8 degrees above the long-term average.

Southeast Queensland’s fire bans came a day after a similar ban was issued for the greater Sydney region as early spring temperatures soared to 33 degrees in the NSW capital.

Maximum temperatures across the city during the first days of September matched the midsummer average of 26.4 degrees, warmer than any other start to spring since observations began.

Severe weather warnings were in place for southeastern Australia over the weekend as damaging winds fuelled the hot conditions.

Jumping castles were picked up by strong winds in two separate incidents in NSW and Victoria on Saturday.

Two children were treated for head injuries at a scene in Banksia, in Sydney’s south, before being transported to hospital.

An infant with minor injuries was also hospitalised, while a woman was treated at the scene.

Two children in Mount Duneed, near Geelong in Victoria’s south-west, were hospitalised after the jumping castle they were using was lifted into the air.

Temperatures are expected to drop in the coming days across both NSW and Queensland.

-with AAP