The World Bank is helping corporations and international investors snap up cheap land in Africa and developing countries worldwide at the expense of local communities, environment and farm groups said in a statement released on Monday to coincide with the bank's annual land and poverty conference in Washington DC.

According to the groups, which include NGO Friends of the Earth International (FOEI) and international peasants' group La Via Campesina, decades of World Bank policies have pushed African and other governments to privatise land and focus on industrial farming. In addition, they say, the bank is playing a "key role" in the global rush for farmland by providing capital and guarantees to big multinational investors.

"The result has often been … people forced off land they have traditionally farmed for generations, more rural poverty and greater risk of food shortages", said FOEI in a separate report launched ahead of the World Bank conference.

The event, which promises to focus on "land governance in a rapidly changing environment", is billed as a forum to discuss "innovative approaches" to land governance challenges including climate change, the growing demand for key natural resources, and rapid urbanisation. But campaigners say the conference mistakenly focuses on how to improve large-scale land deals rather than on helping local communities to secure or retain access to their land.

The FOEI report suggests land grabbing is intensifying and spreading, especially in rural areas of Africa and Asia. "High levels of demand for land have pushed up prices, bringing investment banks and speculators into farming," it says.

"The World Bank's policies for land privatisation and concentration have paved the way for corporations from Wall Street to Singapore to take upwards of 80m hectares (197.6 acres) of land from rural communities across the world in the past few years," said the groups in a statement accusing the bank of promoting "corporate-oriented rather than people-centred" policies and laws.

In 2010, the World Bank spearheaded the development of new principles for responsible agricultural investment to better ensure that land deals respect local rights, livelihoods and resources; these guidelines have also been criticised for legitimising, rather than challenging, the global rush for land.

Allegations of land-grabbing have hit countries around the world and have been accompanied by growing concern about whether large-scale land deals are delivering promised income and employment for local people. This week, a coalition of NGOs and research institutes is expected to release the latest findings of the Land Matrix project, which has attempted to systematically document recent land acquisitions.

Current estimates suggest that 80-230m hectares of land have been leased or bought in recent years, largely to produce food, feed or fuel for the international market.

World Bank money has been involved in many recent international land deals, says the FOEI report. In Uganda, the International Finance Corporation (IFC), the bank's private sector lending arm, contributed $10m for a project to clear 10,000 hectares of land for palm oil plantations on Bugala Island in Lake Victoria.

But FOEI research has shown that local people were prevented from accessing water sources and grazing land, suggesting that – despite promises of employment – many people have lost their means of livelihood.

Resistance to land grabs is growing: Harvard University has come under intense pressure to ensure its investments do not contribute to land grabs in Africa, while Iowa State University has withdrawn from a deal in Tanzania that could have displaced an estimated 160,000 people. In South Sudan, the government halted a land deal after local communities erupted in protest, saying their lands had been secretly leased to an American company.

This month, farmers and land rights activists from across Sierra Leone converged on the country's capital for a national assembly of communities affected by large-scale land deals, where groups launched a new civil-society watchdog to monitor agribusiness investments. The meeting followed the first international farmers' conference to tackle land grabs, held in Selingue, southern Mali, in late 2011.

On Tuesday, food justice activists, environmental organisations, students and Occupy Wall Street groups are set to gather in front of New York's Waldorf Astoria hotel to challenge the fourth annual Global AgInvesting (GAI) conference, where institutional investors and fund managers are meeting to discuss opportunities for agricultural investments overseas.

"Governments around the world need to stop land grabbing, not just try to mitigate its worst impacts. Governments must abide by their human rights obligations on land and drastically reduce demand for commodities such as palm oil from the west," said Kirtana Chandrasekaran, FOEI's food sovereignty co-ordinator.

David Kureeba, from the Ugandan national association of professional environmentalists, said: "People's rights to land [in Uganda] are being demolished. Small-scale farming and forestry that protected unique wildlife, heritage and food is being converted to palm oil wastelands that only profit agribusinesses."

Government officials, civil society, experts and the private sector will gather at the World Bank conference, which ends on Thursday, to discuss large-scale land aquisitions, land governance in the context of climate change, and rapid urbanisation.