A US branch of Wal-Mart. An imminent deal could take the retailer into Zimbabwe.

Could the Waltons soon be doing business under Robert Mugabe's regime? A curious detail in Wal-Mart's $4.6bn (£2.9bn) takeover offer this week for the South African shops group Massmart is that, if successful, it will take the world's biggest retailer into Zimbabwe.

If Wal-Mart buys Massmart, it will inherit Makro warehouse stores in Zimbabwe's two biggest cities - Harare and Bulawayo. While not unusual for a South African company, that could create some unwanted complications for a US corporation.

The US government has had economic sanctions in place on Zimbabwe since 2001, after Mugabe won a discredited election. But they're fairly tightly drawn and Wal-Mart wouldn't necessarily be breaking them - according to the US Treasury, the rules say US companies can't engage in transactions with any Zimbabwean people, entities or organisations found to be "undermining democratic institutions and processes".

The situation in Zimbabwe has changed since Mugabe was forced into a power-sharing deal with opposition leader Morgan Tsvangarai last year. But Washington still has its doubts - the US assistant secretary of state for Africa, Johnnie Carson, met a Zimbabwean delegation only last week and told them that more progress needed to be made before these targetted sanctions would be lifted, citing ongoing human rights violations, land seizures and intimidation of political participants.

Wal-Mart, which owns Britain's Asda chain, wasn't keen to chat about its possible Zimbabwean operation - a spokesman at the retailer's Arkansas headquarters, Kevin Gardner, said: "Since we have only made a preliminary proposal that could potentially lead to an offer, it's premature to discuss specifics."

Richard Branson this month called on the business world to help Zimbabwe get back on its feet - he has been involved in setting up a nonprofit group called Enterprise Zimbabwe, which connects investors interested in the country.

The NGO world is non-commital on the prospect of Wal-Mart's strategy of rock-bottom prices and equally parsimonious wages reaching Zimbabwe. Rona Peligal, deputy African director for Human Rights Watch, said: "We're not against investment unless it violates sanctions. But we do have broad concerns about how any investment is used and the climate in which it takes place."