Three "highly traumatised" women have been rescued from a house in south London where they appear to have been held captive for three decades, Scotland Yard has said.

A 69-year-old Malaysian woman, a 57-year-old Irish woman and a 30-year-old British woman were all rescued from the residential address last month by detectives from the Metropolitan police human trafficking unit.

Two suspects – a 67-year-old man and a 67-year-old woman – were on Thursday arrested at the address under the investigation into slavery and domestic servitude, the force said in a statement.

Scotland Yard said: "Police were contacted in October by Freedom Charity after they had received a call from a woman stating she had been held against her will in a house in London for more than 30 years.

"Further inquiries by police revealed the location of the house and with the help of sensitive negotiations conducted by the charity the three women, a 69-year-old Malaysian woman, a 57-year-old Irish woman and a 30-year-old British woman, were all rescued.

"All three women, who were highly traumatised, were taken to a place of safety where they remain."

Aneeta Prem, founder of the Freedom Charity, said the three women were in effect kept in "domestic slavery" and felt they were not allowed to leave the house because of their fear of their alleged captors.

There did not appear to any sexual element to the alleged captivity, Prem added.

"One of the key things that has come up is that these three ladies were absolutely terrified by these people," she told Sky News.

Prem said one of the woman called the charity's helpline, which led to a week of calls before the operation to release them. The contact was in secret because "they felt like they were in massive danger", Prem said. "With the help of the police we were able to get them out."

The address where they were found was "just an ordinary house in an ordinary street that wouldn't raise any concerns with anybody else", she said, adding that neighbours did not appear to have known anything.

The three presumed victims had access to their own rooms but were "very restricted on everything they could do", Prem said.

The women were all together in a place of safety and were doing well, she added.

Prem said there was concern that the women would not in the end want to leave "because obviously 30 years, being held in a very difficult situation, you become very institutionalised to a very bad way of living, so we had to ensure that when they were going to come out they didn't then decide they were going to go back in".

At a police press conference officers said they believed the 30-year-old woman who was rescued had lived in the house her entire life against her will, and had no contact with outside world that most people would consider normal. The three women were kept under a strong degree of control, officers said. Reports said the house concerned was in the Lambeth borough area of south London.

Detective Inspector Kevin Hyland, from the Met police's human trafficking unit, said: "We applaud the actions of Freedom Charity and are working in partnership to support these victims who appear to have been held for over 30 years. We have launched an extensive investigation to establish the facts surrounding these very serious allegations."

He added: "A television documentary on forced marriages relating to the work of the Freedom Charity was the catalyst that prompted one of the victims to call for help and led to their rescue."