A woman walks past the Royal Albert Hall in London, Britain, on Tuesday. Photo: Xinhua

British lawmakers will hear evidence that aid workers are demanding sex in return for assistance when they launch an inquiry on Thursday into preventing sexual abuse and exploitation in the aid sector.

The industry has come under intense scrutiny since 2018 when it emerged that Oxfam staff had paid young women in Haiti for sex while responding to the 2010 earthquake.

Parliament's International Development Committee (IDC) found similar cases of abuse and exploitation across other organizations and countries during an inquiry following the scandal.

"From what I've heard this is endemic within the aid sector," IDC chairwoman Sarah Champion told Reuters.

"There's a culture that allows this to happen and that's what we need to try to... unpick and stop."

Champion said cases she had come across involved UN agencies and big aid organizations as well as local agents contracted to deliver assistance.

"It seems to be almost an accepted trade in sex for aid, and that I think is what's shocked me most. It's almost like a commercial rate that people are aware of," she said.

"[For] the beneficiaries it's basically you acquiesce to this or you don't eat - and this is from the very people who are in paid employment to try and protect and serve you."

She said some cases involved aid being traded for sex in refugee camps.

The IDC will consider what progress has been made to protect aid recipients from sexual exploitation and abuse by aid workers and peacekeepers since its 2018 inquiry.

In particular, it will look at the mechanisms in place to enable victims to report incidents, how reports are handled and what psychological support and legal advice victims can access.

Britain's government announced in June that it was merging its diplomatic and aid departments in September.

Lawmakers will also look at what action the new Foreign, Commonwealth and Development Office should take to improve reporting of incidents, strengthen independent investigations, support victims and provide access to justice.

When the inquiry begins on Thursday, lawmakers will hear from whistleblowers who have tried to prevent abuse.

Champion said some whistleblowers had lost their jobs after reporting incidents, and the inquiry would look at how well whistleblowers are protected from retaliation.