© Provided by Daily Mail 'NSW, Queensland and Victoria are looking very lean for rain and below average rainfall through summer and heading into next winter,' state's agricultural minister Adam Marshall said Australia is set to swelter for another six months before the first significant rainfall, forecasters have warned.

The Bureau of Meteorology made the stark warning for New South Wales, Queensland and Victoria at a meeting of state and federal ministers in the regional New South Wales town of Moree on Tuesday.

NSW is battling through one of its worst ever droughts, but the state's agricultural minister Adam Marshall said drought-breaking levels of rain were not expected until April or May 2020 at the earliest.

'NSW, Queensland and Victoria are looking very lean for rain and below average rainfall through summer and heading into next winter,' Mr Marshall told The Australian.

'The outlook is nothing for NSW anywhere near drought-breaking until April-May next year.'

Talks at the meeting on Tuesday, which were partly based on a BoM briefing, also involved discussions about drought assistance in some of Australia's worst-affected areas.

'We have agreed to make sure we work together to streamline process (of giving aid to drought-impacted areas) - if there's duplication that can be taken away,' Federal Drought and Water Resources Minister David Littleproud said.

The warning comes as Sydney residents were told to brace themselves for 'unprecedented losses' as the bushfires on the city's doorstep breach its suburbs later this summer, according to an ex-fire chief.

Greg Mullins, who was Fire and Rescue NSW commissioner from 2003 to 2017, said Sydney will likely to experience devastation greater than 1994, when hundreds of suburban homes were lost.

'The worst is to come because it's going to get hotter and drier and there's no significant rain in the outlooks,' Mr Mullins told AAP.

'We've got massive fires that are too big to put out without rain. They are going to get bigger and they are going to come into Sydney suburbs, the South Coast, the Central Coast.'

Six lives have been lost in NSW so far this bushfire season while more than 680 homes have been destroyed.

Mr Mullins said that was three times the previous record number of homes lost, with destruction this year so far confined to regional areas.

'Formerly all of our big losses have been places like the Blue Mountains, Sutherland, Warringah and Lane Cove,' he warned.

Some 225 homes and other buildings were destroyed in the summer of 1993-94, when four people were killed.

The most significant losses were in the Sydney region.

© Provided by Daily Mail The NSW Environment Department said heavy smoke lingering in Sydney is expected to clear on Wednesday thanks to a 'strong southerly'

Head of the Centre for Environmental Risk Management of Bushfires Ross Bradstock said the fires in northern NSW are 'off the scale' and 'nothing like we've seen before'.

'So far, the losses have not been as high as Black Saturday and Ash Wednesday, but both of those events were in February,' he told The Australian.

'It's shaping up to be one of the worst fire seasons in Australia's history.'

Professor Bradstock said December and January are set to bring the biggest bushfire threats due to the lack of rain forecast and the 'sheer size and number of fires'.

More than two million hectares of land has been burned to date this season and there are more than 80 fires currently raging including a so-called megafire northwest of Sydney.