Deloitte is facing criticism from anti-poverty campaigners after the charity ActionAid obtained documentation from the firm advising clients on how to minimise tax payments in some of the poorest countries in Africa.

ActionAid has published details of a Deloitte presentation called Investing in Africa through Mauritius which, the charity claims, suggests clients should not invest directly in Mozambique but channel their money via Mauritius.

Normally, a foreign investor in Mozambique would have to pay a 20% tax on any dividends plus corporation tax, while the sale of a Mozambique-based company would trigger a capital gains tax charge of up to 32%. However, under the terms of a treaty signed by Mozambique and Mauritius, investing via a Mauritian company could reduce dividend taxes to 8% and eliminate capital gains tax, the Deloitte presentation said.

ActionAid claims Deloitte presented the document at a conference for international businesses two weeks before this year's G8 conference in Loch Erne, Northern Ireland, when world leaders promised action to help impoverished nations improve their tax regimes.

Toby Quantrill, ActionAid tax justice policy adviser said: 'This document helps lift the lid on the tax avoidance techniques that are being used to deprive poor countries of hundreds of millions of dollars in tax. These techniques may be legal, but that does not mean they are moral. Tax revenues are desperately needed to meet people's most basic needs and to move countries away from aid dependency.'

A spokeswoman for Deloitte said: 'It is wrong to describe applying double tax treaties, such as the treaty between Mauritius and Mozambique, as tax avoidance. Such treaties are freely negotiated between the governments of the countries involved.'

'Any discussion of tax treaties by tax professionals would typically be around the technical and administrative aspects of the treaties and not an expression of favour of any particular country at the expense of any other country.'