Aggressive moves by China, South Korea and Gulf states to buy vast tracts of agricultural land in sub-Saharan Africa could soon be limited by a new global international protocol.

A scramble for African farmland has in recent years seen the equivalent of Italy's entire arable land hoovered up by businesses from emerging economies.

The Food and Agriculture Organisation, the UN Conference on Trade and Development (UNCTAD) and the World Bank are now discussing a new code of conduct for land buyers in Africa. Amid increasing concerns over food security, it could include ensuring consent is given prior to selling land from local people as well as ensuring smallholders do not lose out. A first draft is expected to be released next spring.

Alex Wijeratna, Action Aid's food rights campaign officer, said: "There's a new scramble for land in Africa. It's growing at an incredible rate. There's massive secrecy, poor communities can't get information and they're not being consulted. There's an argument for a moratorium on sales until there's a proper framework to assess them. We are concerned that an agreement will not come fast enough."

Earlier this year, legendary hedge fund speculator George Soros highlighted a new farmland buying frenzy caused by growing population, scarce water supplies and climate change. South Korea bought huge areas of Madagasca recently while Chinese interests bought up large swathes of Senegal to supply it with sesame.

He said: "I'm convinced that farmland is going to be one of the best investments of our time. Eventually, of course, food prices will get high enough that the market probably will be flooded with supply through development of new land or technology or both, and the bull market will end. But that's a long ways away yet."

However, Dr Kanayo Nwanze, president of the International Fund for Agricultural Development, said the issue of land deals had been "overexaggerated".

As investors pile into African land, today saw further appetite for business opportunities in the continent with the launch of a new $400m (£245m) sub-Saharan private equity fund focusing on small to mid-market companies. Aureos Capital's Africa Fund has already raised $322.8m, a quarter of which has come from financial institutions including European pension funds. It is expected to close fundraising at the end of the year.

The fund is the largest private equity vehicle targeting smaller African businesses. Investors, it claims, will receive returns in excess of 20%. Management fees are 0.25% higher than the industry standard 2% because of the large number of investment professionals it is deploying in Africa to identify suitable opportunities.

Sev Vettivetpillai, chief executive of Aureos Advisers, said: "It's 18 months since we started the fund and it's not easy to raise over $300m for Africa as most investors were pulling out of financial markets. It posed a challenge to Aureos. But Africa is the next frontier market that is going to benefit from emerging market flows."

The fund has already spent $106m on nine businesses in financial services, building products, real estate development and agriculture.