US federal food safety advisors want the US Food and Drug Administration's planned guidelines on mercury in fish to include more information.

A panel of outside food experts said they thought information on fish that are low in mercury and safer to eat should be included, but added that they needed more time to give exact recommendations to the FDA, Dow Jones News reported.

The proposed FDA guidelines advise people, especially women of childbearing age, to limit their consumption of tuna due to concerns about mercury poisoning. Previous FDA guidelines have advised pregnant women to avoid eating shark, swordfish, king mackerel and tilefish due their higher levels of mercury, but have steered clear of advising against tuna consumption due to fears that it could be substituted with a less nutritious food, reported Reuters.

David Acheson, chief medical officer in the FDA's Center for Food Safety and Applied Nutrition, said that many members of the advisory panel had called for information on fish that have lower levels of mercury and details of acceptable potion sizes to be included in the FDA's advice.

The panel is to review transcripts of its meeting and provide detailed advice to the FDA in the coming days, Dow Jones News said.