Premier global construction company Multiplex has completed The Terraces, Presbyterian Aged Care's (PAC) new $180 million over 55's community at the former Scottish Hospital site on Brown Street in Sydney's Paddington.

The Terraces is the biggest single project ever embarked on by PAC in New South Wales.

Multiplex Regional Managing Director David Ghannoum said its completion marked the culmination of a long and rewarding partnership between Multiplex and PAC.

"The redevelopment of this significant site has been a long journey for PAC and we are proud to have helped them along the way both in a development advisory capacity and as their construction delivery partner," he said.

"We are delighted with the end result and are looking forward to seeing this new community continue to flourish."

Designed by Cottee Parker JPR Architects, The Terraces expands over 1.5 hectares and comprises a 100-bed residential aged care facility including a 23-bed dementia unit; 70 over 55's independent living units across four buildings; and the adaptive conversion of the Scottish Hospital heritage building into nine independent living units.

New community facilities include café , hair and beauty salon, cinema, community and function rooms, swimming pool and gym. 1,366 square metres of land will be also dedicated to Woollahra Council as part of the development, to expand the public park on the northern boundary of the site known as Dillon St Reserve.

Presbyterian Aged Care CEO Paul Sadler added: "This is the culmination of a twenty-year journey for PAC and the Presbyterian Church. The Terraces is already coming alive as a vibrant community for seniors in the Eastern Suburbs. And people from across Australia and internationally are visiting to see an iconic inner city aged care development."

The construction of The Terraces was staged to enable the existing aged care facility to remain operational until all residents could be moved into the new part of the development.

Multiplex managed additional construction challenges including restricted access to site from the surrounding residential streets, and challenging landscape topography with the complex built into the side of a steeply sloping hill.

Multiplex also planned works in consultation with an arborist to retain and protect six heritage trees including a multi-trunked weeping lilly pilly on site.

Work commenced in November 2015 with an average of 140 people working on site each day throughout the construction.