Sutherland Shire Council is making a last-ditch effort to stop Telstra mobile phone installations going ahead at Lilli Pilli, Kareela and Engadine.
The council meeting on Monday night approved an appeal against Telstra mounting its installations on council poles, which could lead to court.
Earlier in the night, councillors met with residents from the three suburbs, who have been fighting unsuccessfully to stop the projects because they fear health effects from radiation.
A meeting organised by Lilli Pilli residents on Sunday was attended by about 120 people, including a number from other parts of Sydney, where there is also widespread community concern.
Barrister Ray Broomhall and Lyn Mclean, the head of EMR Australia, spoke about residents' legal rights and health effects from this infrastructure.
The council meeting also decided to hold a community meeting at Sutherland Entertainment Centre, to which Telstra and other telcos will be invited, to thrash out the issues.
The main motion, moved by Cr Kent Johns, spoke of "the genuine community concern in regard to Telstra Base Cell stations (referred to as Telstra Small Mobile Phone Radio communications facility) in Lilli Pilli Point Road".
Similar motions followed regarding installations in Moonbi Place, Kareela, and Croston Road, Engadine.
Lilli Pilli resident Kristen Drysdale, who is fighting an installation outside her home, said outside the council meeting Telstra had cancelled earlier proposals for installations at Caringbah South and Gymea following community pressure.
"Our feedback to them has been 10 times stronger, but they are not listening," she said.
"There has been a rapid change from this infrastructure being located in commercial areas to now being out the front of homes with radiation emitting cells pointing straight into children's bedrooms.
"Telstra only notify residents in about 10 houses and give only 10 days to supply feedback even though this infrastructure emits radiation for a 500 metre radius."
Ms Drysdale said the main concern was that the ARPANSA standards had not been updated since 2002.
"The standards do not protect children, pregnant woman or the elderly and have certainly not been done with long term exposure which is now the norm," she said.
Telstra regional general manager Mike Marom said, after reviewing feedback on the Lilli Pilli site, it had been determined this was the best location for the facility.
"The proposed installation of the small cell utilises 4G infrastructure, not 5G," he said. "There is no 5G infrastructure currently being installed in the Lilli Pilli area".
Mr Marom said a small cell would enhance mobile coverage in the area and enable locals to have improved data services as well as provide increased opportunities for local businesses.
"We take our responsibilities regarding the health and safety of customers and the community very seriously," he said.
"We also acknowledge that some people are genuinely concerned about the possible health effects from electromagnetic energy (EME) and we are committed to addressing those concerns responsibly.
"We rely on the expert advice of both the World Health Organisation (WHO) and the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) for overall assessments of health and safety impacts.
"The WHO and ARPANSA advise that there is no substantiated scientific evidence that radiofrequency technologies that operate within national and international safety standards cause health effects.
"The standards are designed to offer protection for all ages, including children and pregnant women."