Jeremy Hunt, Secretary of State for Culture, Olympics, Media and Sport, told MPs yesterday he was "worried" about the lottery.
He told a Commons select committee on culture, media and sport that the government was looking at the impact of the lottery on good causes.
"I am worried about the Health Lottery, because protecting the income for good causes is a very, very important responsibility that this government has," he said. "And the National Lottery was set up in a way that would generate money for those good causes.
"Society lotteries are allowed on the basis that they are local lotteries."
Asked whether he had taken a view on whether the lottery was legal, Hunt said the Gambling Commission was considering this.
He added: "If they concluded that what was happening was not legal I would expect them to take robust action."
A spokesman for the Gambling Commission said it did not comment on individual operations.
The Advertising Standards Authority confirmed yesterday it had opened a separate investigation into the lottery after receiving 10 complaints.
The complaints related to TV and regional press adverts allegedly being misleading about the prizes.
Martin Hall, chief executive of the lottery, said it aimed to generate at least £50m of new, additional money for good causes, and in its first three weeks more than £1m had already been donated to community initiatives.
"We know from recent data that sales in the National Lottery are in fact £50,000 higher per draw since the launch of the Health Lottery, proving the marketing maxim that a launch will also drive sales for the market leader and generally refresh consumer interest in a category," he said.
He added that a disproportionate amount of good cause funding from the National Lottery was allocated within the M25, but that the structure of the Health Lottery meant there would be a more even spread of funding for good causes.