THE Federal Government has assured Adelaide its water is secure despite the Murray River hitting record lows.

Murray-Darling Basin Authority chief executive Rob Freeman says the authority can't guarantee the water will be delivered over the next two years.

Mr Freeman says inflows to the Murray during the past three months have been the lowest ever recorded.

But Federal Water Minister Penny Wong says the water is secure for 2009/10.

"The best advice that the governments have ... is that we will be able to secure critical human needs,'' she told reporters in Adelaide on Thursday.

"I understand that is absolutely the priority of the way in which all governments will approach this issue.

"The first priority from the River Murray is to ensure that we have drinking water for Adelaide and the water that is absolutely essential for Adelaide and Adelaide's businesses.

"There is already security in relation to the quantum of actual water required.

"But what is the issue is the conveyance water.

"Obviously as the months progress and we are heading into the winter period, that will continue to be the first priority because the first priority cannot be water for any other use than critical human needs, including the conveyance water.

"In terms of ongoing contingency arrangements, this is why we have to diversify our water supply, we do need to ensure that we have a range of secure water sources for Adelaide and other towns along the Murray.''

Mr Freeman said South Australia shouldn't panic about the supply of water.

"The stakes are high, the risk is very small and even the worst ever year that we've had, this is secure,'' he told ABC Radio on Thursday.

"What I'm saying is that we may have a worse year, bureau of met (meteorology) are predicting lower than average rainfalls so we are in a pretty dire situation.

"However I think it's important that we don't leap to an extreme.''