The national lottery may be hit by a £5 billion shortfall for the "good causes" it was set up to fund.

When Camelot was awarded the contract to run the lottery it, along with Richard Branson's People's Lottery, estimated that £15 billion could be raised to back worthy projects.

But lottery regulator, Lord Burns, has warned that sales are unlikely to top the current £5 billion a year and that good causes should anticipate £10 billion being raised over the seven year lifetime of the next lottery license.

The £10 billion figure would be in line with the amount expected to be raised for good causes over the present lottery license, Burns said to the Lottery Monitor Conference in London on Wednesday.

"Camelot's principal forecast was based on raising £15 billion for good causes and we would be delighted to see it achieve this. International experience, however, suggests that lotteries' sales decline after their initial life-span and there is more competition to the National Lottery now from other gaming markets than there was when it started in 1994. This is why we take a cautious view of possible future sales," said Burns.

A statement from Camelot said that meeting its aim of raising £15 billion for the good causes would depend on whether the Commission agreed to the games in its license bid, support from its partners involved in the lottery and any regulatory changes to gambling regulations.

The statement added that Camelot would "revisit" the issue of fund raising with ministers and the Commission.

The new National Lottery licence has also been published, setting out plans to maximise income for good causes.

Measures include linking the amount retained by Camelot to the amount raised for charities rather than sales as used at present, commitments to spending on marketing the lottery and interest at three per cent above base rates on any late payments into the distribution fund.

In addition, half of any profits Camelot makes in excess of its own principal forecast will be paid over to the Good Causes.

"The result of the competition we staged is a new lottery licence that strongly supports the UK National Lottery's record in recent years. Measured in terms of total contribution to good causes and the exchequer, the UK lottery is among the most successful in the world," concluded Burns.

Money raised by the lottery is currently distributed between several areas: health, education and the environment via the New Opportunities Fund, arts, sport, heritage and charities.

The government also announced that a £150 million of lottery funds will be used to target deprived parts of the country, and areas that have so far received less than their fair share of Lottery proceeds.

The new fund uses £100million from the Community Fund and £50 million from the New Opportunities Fund and will be focused on 50 areas of the country over the next three years.

Culture Secretary Tessa Jowell told the conference that the fund would deliver results without imposing more red tape.

"It will be used to help fund projects like community halls, local environmental initiatives and after school clubs - things that help to build communities, and bring people together for the good of all," said Jowell.