A large turnout is expected for an on-site court hearing over plans for a seven-storey apartment block near Coles at Engadine.
Parents with children at two childcare centres, along with nearby residents, are strongly opposing the project in Boronia Avenue.
Concerns include are overshadowing, privacy and the safety of children accessing nearby schools.
A Land and Environment Court commissioner will inspect the area and hear views on Monday, June 24.
The developer lodged a development application (DA) for the $11 million project in October last year, but rather than wait for a local planning panel decision, has taken the matter to court on the grounds of "deemed refusal".
Engadine Gumnut Child Care Centre, which has been operating for 40 years, is just two doors from the proposed development site.
Sisters Allyson O'Keefe and Kim Maher, who have owned the business for 13 years, said parents were strongly opposed to the DA.
"Gumnuts back play area will be completely in shade for all afternoon play time during the colder winter months," Ms O'Keefe said.
"The shade will also greatly affect our neighbour's house all year around and other houses as well, creating an unhealthy environment with no access to sun in winter.
"This will increase electricity cost, for heating and clothes drying, along with damaging our gardens.
"Our solar hot water system will also lose access to sun for many months of the year, restricting our hot water for the kitchen and increasing power cost.
"We will also lose the warmth of the sun across the centre building during the colder season."
Ms O'Keefe said privacy was a concern because more than 40 windows would overlook the childcare centre yard. The traffic situation was also concerning, she said.
"Boronia Avenue is already very extremely busy, with street parking full by 8.30am most weekday mornings," she said.
"This development would add to an increase in illegally parked cars or double parking as children are picked up from local schools and two childcare centres."
Ms O'Keefe said the proposed unit block had no visitor parking in the plans and only 40 car spots for 31 units.
The owners of the adjoining property said their home would be "severely impacted by the bulk and scale of the proposed development".
"We are both age pensioners and my wife is suffering ill health," the resident's written submission said.
"The dust, noise, disruptions and lack of sun light will have adverse effects on her health..."
"We object that the developers would leave a residential house by itself squished in between a 6/7 story unit block and a kindergarten."
