Foreign companies that are listed on the London stock market but have no other presence in the UK should not be liable for prosecution under the Bribery Act, according to guidance being drawn up by the Ministry of Justice.

Draft wording, seen by the Guardian, appears to indicate that the justice minister, Kenneth Clarke, is seeking to tightly define the scope of the otherwise wide-ranging act, which was passed by parliament in the last days of the Labour government.

The act has been attacked by the business lobby, with the CBI director general, John Cridland, calling it "not fit for purpose". In January, Clarke bowed to pressure, delaying its introduction in response to pleas from what he said were "frightened" corporations seeking further guidance on how it would be implemented. Britain has been promising to introduce such an act since it ratified the OECD's anti-bribery convention 13 years ago.

Last-minute clarifications, which could be published as early as next week, are likely to be closely scrutinised by anti-bribery campaigners, some of whom are concerned that Clarke is drifting beyond his powers, using departmental guidance to recast primary legislation.

Last month Clarke promised counterparts in the US that the act would not be watered down. Meanwhile, many experienced anti-fraud prosecutors believe the act should not – and indeed cannot – be diluted through post-legislative ministerial guidance. Robert Wardle, a former Serious Fraud Office director who sits on the CBI's anti-bribery group, said: "This is absolutely an act 'fit for purpose'. It is designed to prevent or suppress the type of conduct which undermines economic development in third-world countries."

Attempts to exempt London-listed foreign firms with no UK corporate presence from compliance with standards on bribery prevention will be welcomed by many in the City, who believe the appeal of UK's capital markets – which have attracted scores of overseas firms in recent years – would otherwise be greatly undermined.

The wording of the act makes clear that an offence of failing to prevent bribery applies to all corporate entities carrying on all or part of a business in the UK.

However, draft guidance being drawn up by the Ministry of Justice before the act comes into force clarifies: "The government would not expect, for example, the fact that the company's securities have been admitted to the UK listing authority's official list, and therefore admitted to trading on the London stock exchange, in itself to qualify that the company is carrying on a business in the UK … for the purposes of [the act]."

In recent years the London Stock Exchange has gone to great lengths to court overseas groups, conducting sales roadshows expounding the benefits of coming to the UK to raise equity capital.

Among high-profile companies listed on the stock exchange but not incorporated in the UK are the gambling groups PartyGaming and 888 and the insurer Hiscox. These companies do however have significant operations in the UK. Most of the FTSE's largest mining groups also have little more than a token holding company incorporation in the UK, to accompany their London market listing. Such firms include the blue-chip businesses Vedanta, ENRC, Kazakhmys and Fresnillo.

It may be impossible to find a company which has a London stock market listing and no presence, even through an agent company, in the UK. Though this makes it all the more puzzling why the Ministry of Justice is choosing to raise such a hypothetical example in its draft guidance. It will do nothing to allay fears the Clarke is seeking to row back on the act.

A spokesman for the Ministry of Justice said: "We cannot comment on unfinished draft guidance which is yet to be made public. It will be for the courts to decide in initial cases whether foreign companies which have a presence in the UK fall under the scope of the offence."