The International Monetary Fund says there is uncertainty about the outcome of Britain's referendum on leaving the EU could cloud an otherwise positive outlook for the country's economic growth.

In its regular report on Britain’s economy, the IMF broadly endorsed Finance Minister George Osborne's plans to run a budget surplus by 2019/20, although it urged flexibility in case of slower growth. It also said the Bank of England may need to get tougher on mortgage lending.

The organization said vulnerabilities for Britain included a "strikingly large" current account deficit which left it exposed to a loss of foreign confidence, as well as high levels of household debt.

"In addition, uncertainty associated with the outcome of the planned referendum on EU membership could weigh on the outlook," the report said.

Osborne, who has been at loggerheads with the IMF in the past, said that overall the report was the most positive since he became finance minister in 2010.

"They say that our economy is much stronger, more resilient and has more jobs," he told reporters.

IMF Managing Director Christine Lagarde said the Fund would assess the alternatives to Britain's membership of the EU in its next report which is due in May.

She said that, speaking personally, she hoped Britain would stay in the bloc.

EU membership has long been a contentious topic in Britain. Eurosceptics, who believe the UK would be better off outside the political and economic union, seek the UK's withdrawal from the EU.

Various polls have indicated that the British public is divided on the issue.

Prime Minister David Cameron has said he will hold the referendum by the end of 2017, after attempting to safeguard Britain's financial sector status outside the euro zone and restrict EU migrants' access to British welfare benefits.