The Hunter will get 50 new paramedics, but they will be based at a Sandgate industrial site because stations at Swansea and Gateshead aren't built.
Alterations are occurring inside the warehouse-type building to make it suitable for the paramedics' arrival.
Brendan McIlveen, an Australian Paramedics Association NSW assistant secretary, said the state government was behind schedule on the two planned Lake Macquarie stations.
"The stations were supposed to be built two years ago," Mr McIlveen said.
However, the association endorsed the Sandgate move as a temporary measure because "we need new paramedics now".
"It will work for the need. It is a big building," he said.
Paramedics have for years faced increased workloads and staff shortages, amid a growing crisis in the NSW health system.
The association, which is a trade union, would like the new paramedics to be based in new, fit-for purpose stations as soon as possible.
"We'd like the health minister and premier to crack on and get some actual locations of where these buildings will be," Mr McIlveen said.
He said the public from those two areas should have their ambulance stations nearby.
A Health Infrastructure NSW spokesperson said "planning for new ambulance stations serving Swansea and Gateshead is continuing to progress".
"Health Infrastructure and NSW Ambulance are conducting a thorough land search to identify potential locations," the spokesperson said.
"The community will continue to be updated as planning progresses."
NSW Regional Health Minister Ryan Park said planning for the new stations and recruitment for the extra paramedics "remains underway".
"Access to healthcare for our regional communities is a top priority," Mr Park said.
The Sandgate site was due to open in mid-July, but may be delayed until September.
A NSW Ambulance spokesperson said it does use "temporary facilities to create additional capacity".
This occurs during construction of a new station or major renovation of an existing one.
New ambulance stations are also planned for Branxton, Edgeworth and East Maitland.
The temporary Sandgate site will also be used to house new paramedics and ambulances for those areas, while their stations are commissioned and built.
"An additional 12 paramedics are planned to be working out of the existing Birmingham Gardens Ambulance Station in the coming months," the spokesperson said.
Mr McIlveen, a Newcastle-based paramedic, said "the NSW government needs to start forward planning the purchase and acquisition of sites for all announced ambulance stations within the greater Hunter".
"We're not aware of acquired sites for any of them."
The government was "well and truly behind in finding station sites statewide".
"The current infrastructure we've got in the Hunter is very aged. Hamilton is 100 years old.
"We can't fit any more staff into that building."
The Swansea and Gateshead crews will have 25 paramedics each.
They will have rosters with two day shifts, along with afternoon and night shifts.
"The other big aspect to this is that the government and NSW Ambulance haven't confirmed those rosters will be maintained every day," Mr McIlveen said.
"I've requested that all the shifts be maintained to ensure there's greater coverage for the community."
He said the issue falls under the controversial PAR [paramedic approved rosters] system.
"It's a big statewide issue. The taxpayers are being told they're getting all these extra paramedics on the road, but NSW Ambulance isn't maintaining them on a daily basis.
"The association thinks this is due to pressure to limit overtime spending in the health budget."
The NSW Ambulance spokesperson said consultation over rostering was ongoing.
An additional 2500 ambulance staff will be employed across NSW, including 500 paramedics in rural and regional areas.
This was part of the $1.76 billion, four-year Strategic Workforce and Infrastructure Team (SWIFT) program, which began in 2022-23.
Under this program, 30 new ambulance stations and "hundreds more ambulances" are being established statewide.
