Barclays has come under fire for promoting the use of offshore tax havens as a route for companies investing in Africa.

In a report published on Wednesday, the NGO ActionAid says Barclays' marketing of offshore tax jurisdictions undermines the bank's stated ambition to be a "force for good" as these places can be used by companies to reduce the tax paid in the African countries where they work. The report does not directly accuse Barclays, or the companies it works with, of tax avoidance, or suggest any illegal activity.

"If people want to put their money offshore, they'll find a way to do it, but Barclays should stop promoting this. It is inappropriate for a bank looking to be a force for good, and aiming to expand its operations in Africa, to do this," said Toby Quantrill, tax justice adviser at ActionAid.

He said Barclays should do more to help companies invest directly in African countries. "If you're going to be a big player in Africa, you should promote and support the development of infrastructure for direct investment in these countries."

Estimates suggest African countries lose billions of dollars in unpaid taxes each year – and far more than they receive in foreign aid. Tax has risen up the global development agenda in light of such figures, with NGOs and high-level officials condemning tax avoidance as putting at risk poor countries' prospects for development and self-sufficiency.

Barclays said it does not encourage businesses to set up in any particular jurisdiction.

Earlier this year, Kofi Annan, the former UN secretary general, said it was "unconscionable" for companies to use unethical tax avoidance to maximise their profits "while millions of Africans go without adequate nutrition, health and education".

ActionAid estimates suggest that almost one in every $2 of reported corporate investment in developing countries is routed from or via a tax haven, with Mauritius the largest player.

In a corporate brochure published on Barclays' website, Mauritius is promoted as "the offshore financial centre of choice for India and the sub-Saharan region" and "the experienced and established gateway for investment into Africa and Asia".

Mauritius is known for its secrecy, negligible corporate tax rates, and for being a favoured conduit for wealthy individuals and multinationals wishing to avoid tax on African and Asian profits.

The Barclays brochure adds that Mauritius offers double taxation treaties with dozens of countries including several in Africa. "There are no exchange controls thus allowing free repatriation of profits and capital with no withholding tax. There are no capital gains, death, wealth or gift taxes," it says.

A previous version of the brochure, seen by the Guardian, also said the bank's offshore corporate team could help companies "make the most of every tax advantage available" in the offshore jurisdictions where the bank operates. The text has since been revised to clarify that Barclays does not itself provide tax advice, and that companies should talk to independent tax advisers.

Quantrill said it was inappropriate for Barclays to be marketing the use of offshore tax jurisdictions given their role of these places in helping companies reduce their tax paid in African countries.

A Barclays spokesman said: "Barclays shares ActionAid's objective that companies and individuals pay the right amount of tax in each country where they do business. While we appreciate ActionAid's concern in this matter, we do not believe that their interpretation of some of the facts is correct. Barclays does not encourage businesses to set up in any particular jurisdiction and we also ensure that tax planning undertaken by Barclays, including that undertaken for clients, complies with our published Tax Principles. As such, tax planning must support genuine commercial activity and be of a type that the tax authorities would expect, amongst other requirements. This applies equally to activity in Mauritius as it does to the remainder of Barclays' operations."

Barclays is the largest UK bank in Africa, with operations in 17 countries. It also has 140 subsidiaries in Africa, compared with Standard Chartered (37), HSBC (15), and RBS (1). Barclays has said it aimed to further expand its operations and reach on the continent to become the "go-to bank in Africa".

ActionAid is calling on the bank to close its offshore corporate department, publish detailed information about its tax strategy and provide evidence that its activities in tax havens are not linked to tax avoidance.

Rather than encouraging companies to use offshore tax jurisdictions, Barclays should be supporting revenue authorities in Africa to strengthen their systems and help build their knowledge and capacity, the NGO says.

"Barclays needs to do far more to show that it is living up to the standards and principles that it sets for itself and that it is able and willing to act responsibly and to become a positive force for good in Africa," says the report. "Promoting the use of tax havens as a way of channelling investment into Africa cannot be considered as supporting responsible investment and sustainable development for all."

The ActionAid report, Time to clean up: how Barclays bank promotes the use of tax havens in Africa, follows criticism of the global consultancy firm Deloitte, which has been accused of advising big business, including UK firms, on how to avoid paying tax in some of Africa's poorest countries.

It also follows a six-month campaign by academics, NGOs, and MPs to stop Barclays' from closing the accounts of major money-transfer companies operating in Somalia.

Barclays announced in May that it planned to shut the accounts of hundreds of money-transfer businesses, citing the lack of adequate money-laundering controls. Critics said the move would particularly damage poor communities in Somalia that often depend on money sent home by friends and family members abroad.

Dahabshiil, which won a temporary injunction at the UK high court this month to stop Barclays from cutting its services, claimed the British bank was abusing its dominant position. Barclays said it would appeal against the verdict.