The charity's speaking after David Cameron delivered a speech in Singapore, which announced various measures to stop foreign investors using laundered money to buy British properties.
These include the Land Registry publishing all foreign companies which own property in England and Wales from Autumn, and opening up a consultation process into other measures to stop corruption in the UK property market.
The Prime Minister said London's property market must not be providing "a safe haven for corrupt money" used by "anonymous shell companies."
It is unclear whether any additional measures from the consultation process will be applied to properties which have already been bought by foreign investors, and what punishments they will receive if it's found corrupt money has been used buy them.
Toby Quantrill, Principal Economic Adviser for Christian Aid, told Premier's News Hour:
"There's over 50 billion dollars worth of resources flowing out of Africa every year [through corruption]. That's huge.
"That's equivalent to the amount of aid flowing in. This is doing huge damage in terms of taking money that could be invested in companies, in new businesses, but also, it was money that could be taxed by governments in Africa to build roads, provide schools, hospitals, and so on, so this is doing real damage."
"Over two square miles of London are owned by companies registered offshore. That is, we have no idea where the money comes from that was used to buy those properties, we have no idea who really sits behind those companies and who really owns that property.
"There is a question of how far this [Cameron's planned reforms] would be retrospectively applied [to properties already bought]. It could be... So we'll be pushing hard to say 'can this be retrospectively applied to existing properties to find out who owns it?' and their may be penalties that could be applied using the properties themselves."
"122 billion pounds worth of UK properties are actually owned in offshore tax havens, many of which are controlled by the UK... What we need to be sure of is that those places also create open registries [like the Land Registry is doing in England and Wales] of who owns and sits behind the companies registered there."
Listen to Premier's Antony Bushfield speaking to Toby Quantrill on the News Hour:
