A 70-year-old man has been ordered to face a New South Wales court in March over allegations he took a boy from a government-run home for wards of the state to a Sydney restaurant and indecently assaulted him under the table.

His arrest is part of a police investigation into an alleged paedophile ring that operated between 1965 and 1985 at Daruk Training School, near Windsor.

Detectives are focusing on a series of excursions during which children at the home were allegedly taken away and sexually assaulted by paedophiles.

The excursion program was designed for troubled boys and often involved taking boys out for lunches. A police operation, known as Strike Force Eckersley, was established in late 2016 to investigate following a series of complaints made to the royal commission into institutional responses to child sexual abuse.

“We will be alleging before court the arrested man indecently assaulted a boy at one of those lunches,” Detective Superintendent Brett McFadden said.

“We are also alleging the suspect was not employed at the Daruk Training School but was a friend of staff who took the child to lunch.”

The man was arrested at 9.30am at a home in Menangle, in Sydney’s south-west. Police also searched the home. The man is due to appear at Penrith local court on 19 March.

Strike Force Eckersley made a public call in March for victims of abuse at the now defunct Daruk training school to come forward. It followed the arrest of a 67-year-old Queensland man allegedly linked to a paedophile ring based at the home. Following the arrest McFadden said detectives were investigating dozens of alleged offenders, and that 80 boys at the home – mostly aged 10 to 14 at the time – endured “significant sexual abuse”.

Investigations are continuing.