The Trade and Industry Secretary, Patricia Hewitt, will this week meet the president of the Democratic Republic of the Congo, Joseph Kabila, to discuss a damming United Nations' report into the illegal exploitation of natural resources.
De Beers, Oryx Natural Resources, Avient Air and Das Air were last year named in the report, which found that their activities may have helped to fund the war in the Republic that has claimed the lives of 2.5 million people.
The British Government is pressing the UN for further evidence of claims that the companies breached business ethics set by the Organisation for Economic Co-operation and Development (OECD).
In the meeting on Thursday with Mr Kabila, Ms Hewitt is also expected to support plans to establish an anti-corruption unit in the Republic. Well-placed sources revealed that Ms Hewitt would pledge government money to set up the unit, which also has the blessing of the Department for International Development.
The unit would be staffed by Congolese officials but may also include civil servants from European Union member states. Its remit would be to investigate cases of alleged exploitation in the Republic.
The British Government has complained that there is insufficient evidence in the UN report itself to enable it to take action against the four companies. It is pressing the UN to release its as-yet unpublished dossier of material. However, it is understood that Ms Hewitt is now keen to move the agenda on to ensure that exploitation of resources is stamped out in the future.
Some campaigners believe the Government is still not doing enough to investigate the allegations against the companies named in the UN report. In the next two weeks, Human Rights Watch, Global Witness and Rights and Accountability in Development will present Ms Hewitt with their own reports of alleged breaches of OECD guidelines. The four companies named in the UN report have denied that they breached the guidelines.