Controversial scheme which gives corporations privileged government access to be extended to a total of up to 80 firms

The government is expanding a controversial scheme which pairs dozens of multinational companies with a ministerial "buddy", giving them privileged access to the heart of government, the Guardian has learned.

The minister for trade Lord Green launched the "strategic relations" initiative in July 2011, giving 38 companies, including oil, telecoms and pharmaceutical giants, a direct line to ministers and officials.

The Guardian has obtained a list of 12 further companies which have now been added to the programme, and understands that UK Trade and Investment is considering up to 30 more for addition over 2013.

Analysis of official registers reveals the 38 companies in the first wave of the initiative – more than two-thirds of which are based overseas – have collectively had 698 face-to-face meetings with ministers under the current government, prompting accusations of an over-cosy relationship between corporations and ministers.

The full degree of contact between the chosen companies and the government is not known as telephone calls, emails, and meetings with officials are not recorded on the registers.

Campaigning groups expressed alarm at the level of access that some of the businesses appeared to have to ministers. The Guardian figures, which looked at the meetings the companies held with No 10 and the three departments involved in the buddy scheme – Business, Culture, and Energy and Climate Change – suggested Shell had the greatest access to ministers. The oil giant has had 56 face-to-face meetings since May 2010.

Greenpeace said this consistent access was showing through in government policy.

"The concern about the government's buddy system was always that policy would end up skewed towards narrow corporate interests rather than the wider public good, and these revelations will do nothing to allay those fears," executive director, John Sauven, said.

Other signs of the scheme bearing fruit for business have arisen in public statements made by the universities minister David Willetts. Last week he urged officials to prescribe more of an Astrazeneca drug, and in November he met Novartis officials about streamlining and accelerating UK research and development and clinical trials – something advocated by many clinicians, as well as businesses.

Among the first wave of "buddied" firms were some which have been targeted by campaigners for paying little or no UK tax, or making "sweetheart" deals with tax authorities, including Google and Vodafone. A spokeswoman for UK Uncut, which campaigns against tax avoidance and spending cuts, said the regularity of government access for big business was drowning out other voices.

"There are hundreds of thousands, if not millions, of people who have marched, written to MPs, gone on strike, protested and occupied over the cuts and privatisation which are devastating our lives," she said.

"These demands by ordinary people have been ignored by a cabinet of millionaires which is choosing to only take the calls, the meetings and the dinners with big business and the banks to introduce policies which benefit them and the wealthy minority in this country."

The new companies to be given ministerial buddies – but not yet publicly disclosed – include the property firms Atkins and Balfour Beatty, which have been paired with climate change minister Greg Barker, who is overseeing work on the government's green deal and zero-carbon homes programmes.

David Heath of the Department of Agriculture is paired with food businesses Nestlé, Unilever, Mondeléz (formerly part of Kraft, and includes Cadbury) and Associated British Foods (owner of Primark and Kingsmill). Statoil is added to the oil companies already in touch with Vince Cable; foreign office minister Hugo Swire has been buddied with Procter and Gamble, and David Willetts with Cisco. The culture minister Ed Vaizey is paired with Telefonica (O2) and Everything Everywhere (Orange and T-Mobile), while Green adds engineering firm GKN to his list.

A spokesman for UK Trade and Investment confirmed the government was considering adding "around 30" more companies to the strategic relations programme over 2013.

"As previously, companies will be selected based on a range of criteria, including the complexity of their relationship with government (and hence the need for strong co-ordination) and their existing or potential contribution to the UK economy," he said.

"Understanding business concerns and being clear about government's own priorities can make a real difference to trade and investment."

A Department for Business, Innovation and Skills spokesperson said Willetts was responsible for the "strategic relationship management" for several pharmaceutical companies, including AstraZeneca. "He regularly meets with companies to discuss issues of importance to them, and has a strong interest in making sure that the environment for the life sciences industry is conducive to innovation and growth."

The Federation of Small Businesses defended the relationship with the government, saying members had good access to ministers through representation by the federation at regular meetings with ministers, but the government could do more.

A spokeswoman said: "We support schemes where multinationals support small businesses in the supply chain and give advice and support through mentoring, for example, such a scheme was announced between UKTI and Diageo in 2012. We would like the government to play an important role in encouraging, promoting such schemes, and engaging small businesses more in the process."

The FSB had 34 meetings with ministers in the four departments analysed by the Guardian between May 2010 and June 2012.