Nick Clegg has called for global action against tax-dodging firms as he embarked on a G8 trip to Africa, arguing that tackling abuses would bolster public support for increasing foreign aid.
As part of the UK's presidency of the G8 group, the deputy prime minister is to begin a three-day tour of Mozambique and Ethiopia.
He will meet politicians and diplomats from across the continent as well as UK firms running successful operations in the region.
He said: "Many of the difficulties that governments face in the developing world are becoming increasingly common in the developed world.
"For too long, the developed world ignored the way in which tax revenues, which rightfully belonged to developing countries, disappeared as people exploited different tax regimes, and made a mockery of governments in the developing world. We must work together to overcome it.
"To disrupt the vicious cycle of inequity in the systems of tax and trade, we must first create a level playing field whereby responsible and thriving companies are attracted to trade and do business in a fair and transparent way.
"As the UK will meet its promise to spend 0.7% of GNI on international aid in 2013, it is vital that the benefits of aid are not wiped out by losses sustained by multinationals or individuals gaming countries' tax systems."
Clegg, accompanied on the visit by International Development Minister Lynne Featherstone, is due to meet the presidents of both countries.
Featherstone said boosting tax revenues would help developing nations "stand on their own two feet"
"Helping developing countries to collect taxes means they can improve their own public services such as health and education. It also helps attract the investment and trade they need to grow and develop."
Officials said trade between the UK and the two countries was "booming" - with exports to Mozambique nearly doubling last year and more than doubling to Ethiopia in 2011.
Among projects funded by UK aid to be visited by the ministers are a mobile phone banking system, and a UK firm making ethanol from root vegetable cassava to replace health-damaging charcoal for cooking and fair-trade