The scale of the rush by speculators, pension funds and global agri-businesses to acquire large areas of developing countries is far greater than previously thought, and is already leading to conflict, hunger and human rights abuses, says Oxfam.

The NGO has identified 227m ha (561m acre ha) of land – an area the size of north-west Europe – as having being reportedly sold, leased or licensed, largely in Africa and mostly to international investors in thousands of secretive deals since 2001. This compares with about 56m ha identified by the World Bank earlier this year, again predominantly in Africa.

The new land rush, which was triggered by food riots, a series of harvest failures following major droughts and the western investors moving out of the US property market in 2008, is being justified by governments and speculators in the name of growing food for hungry people and biofuels for environmental benefit.

But, says Oxfam, "many of the deals are in fact 'land grabs' where the rights and needs of the people previously living on the land are ignored, leaving them homeless and without land to grow enough food to eat and make a living".

"Many of the world's poorest people are being left worse off by the unprecedented pace of land deals and the frenetic competition for land. The blinkered scramble for land by investors is ignoring the people who live on the land and rely on it to survive," said Oxfam chief executive Dame Barbara Stocking.

Oxfam expects the land grabbing to increase as populations grow. Its report said: "The huge increase in demand for food will need to be met by land resources that are under increasing pressure from climate change, water depletion, and other resource constraints, and squeezed by biofuel production, carbon sequestration and forest conservation, timber production, and non-food crops."

While some investors might claim to have experience in agricultural production, many may only be purchasing land speculatively, anticipating price increases in the coming years, a practice known as 'land banking'.

In addition, developing countries are under pressure from the IMF, the World Bank and other regional banks to put farmland on the international market to increase economic development and improve the balance of payments.

Much of the land grabbing has being driven by the expansion of sugar cane and oil palm for biofuel production. "Thousands of people have been persuaded to part with their land on the basis of false promises in Indonesia, or have been evicted from their lands and their homes in Uganda, Guatemala and Honduras," says the report.

Most of the land deals done in Ethiopia, Ghana, Mali, Mozambique Senegal, and Tanzania have been to grow crops for export commodities, including cut flowers as well as biofuels. In Mozambique, where approximately 35% of households are chronically food insecure, only 32,000 ha out of the 433,000 approved for land deals between 2007 and 2009 were for food crops.

The report said: "Unrestricted export clauses in contracts, together with small-scale food producers losing their key productive asset, may well worsen rather than improve food security. Moreover, investors' short time scales may tempt them into unsustainable cultivation practices, undermining food production in the long-term.

Stocking called on the EU to scrap the incentive offered to investors to grow biofuel crops, and organisations like the World Bank to ensure that local people are consulted on land deals.

"Governments should avoid pandering to investors' wishes, and prioritise existing land use rights – not just where legal land title or formal ownership rights are held," said the report.

Stocking said: "Land investment has great potential to help people work themselves out of poverty, but the current rush for land is leaving people worse off. Global action is crucial if we are to protect local people from losing what little they have for the profits of a few, and build towards a tomorrow where everyone has enough."