More than 20 charities, including Oxfam Great Britain, have pledged to boost safeguarding and are calling on people to report unacceptable behaviour.
The aid agencies said there can be no tolerance for "the abuse of power, privilege or trust" within their organisations, and said they are "truly sorry" that their sector has at times failed.
The open letter, published on the Huffington Post website and signed by 22 charities, comes a day after Oxfam GB was temporarily suspended in Haiti pending an investigation into how the charity handled the case of former staff paying for sex.
Mark Goldring, Oxfam GB's chief executive, signed the letter which said charities have "an absolute duty" to do everything they can "to prevent, detect and eradicate unacceptable behaviour".
Other charities among the 22 are Save the Children UK, UNICEF UK, Muslim Aid, CAFOD, Christian Aid, and WaterAid.
"Safeguarding is something that, as a sector, we have long taken very seriously and all our organisations have systems in place to prevent all forms of abuse and misconduct.
"However, we can never be complacent. We must do even more to protect the very people we were set up to help," the agencies wrote.
They added: "We will all increase the resources we devote to safeguarding - meeting our responsibility to protect our staff and beneficiaries.
"We will collectively review our current referencing systems so that people found to have abused their power or behaved inappropriately are not re-employed in the sector - including in INGOs, government agencies, the UN and other associated bilateral and domestic agencies.
"We will work with these authorities and regulatory bodies to ensure any individual caught abusing their power cannot do so again.
"We will work with the Government to ensure that we can overcome the legal and institutional barriers to rigorous background checks in the UK.
"In taking these steps, we are also asking people to come forward to report unacceptable behaviour. We hope these measures send a clear message to those who experience or witness any form of abuse - it is really important that they know that we will listen and we will take action.
"These actions are only the first step as, collectively and individually, we do everything possible to ensure that our organisations, our staff and the work we fund meets that most fundamental criteria for all charities - to serve people and not to exploit them.
"We are truly sorry that at times our sector has failed. We must and will do better."
Mr Goldring publicly apologised for the actions of charity staff who sexually exploited female victims of the 2010 earthquake in Haiti.
Oxfam GB's two-month suspension came after charity chiefs revealed Oxfam has received 26 allegations of misconduct since the Haiti sex scandal erupted two weeks ago.
Mr Goldring said 16 of the claims stemmed from abroad, while 10 came from the UK.