New homes and schools should not be built within 60 metres of high voltage power lines until the link with childhood cancers is better understood by scientists, according to a committee of MPs. They also recommend that home buyers should be provided with information on the level of electromagnetic fields within homes before they buy.

The committee says the science is still unclear and that any health effects are weak, but in the meantime it argues that the government should adopt a precautionary approach.

The Labour MP and GP Howard Stoate, who chaired the committee, said: "The overall body of evidence shows that there is undoubtedly a link between living near very high voltage power lines and childhood leukaemia. We can't say that one causes the other but we can say that there is an association."

He added: "I've always got the view in science that if you don't know something it is generally better to err on the side of caution, rather than to look back in 20 years time and say, if only we had done more 20 years ago."

The most influential scientific study on the issue was published two years ago in the British Medical Journal. It looked at the health records of nearly 30,000 children with cancer, including 9,700 with leukaemia and a similarly-sized group of healthy children. The study found that those within 200 metres of power lines had a 70% increase in their chance of developing leukaemia, compared with children living more than 600 metres from a power line.

Other epidemiological studies have failed to find a link and as yet no one has come up with a convincing biological mechanism that would explain how electromagnetic fields from power lines could cause cancer.

The committee of five MPs heard estimates of the number of excess cancer deaths attributable to power lines ranging from two to 60 a year.

The committee says the government should introduce a moratorium on home and school building within 60 metres of high voltage power lines and 30 metres of low voltage lines. It also says that new power lines should not be built within 60 metres of homes and schools, and a larger building moratorium extending to 200 metres should be considered.

In evidence to the inquiry, Barratt Homes estimated that homes close to power lines already sell for 15-25% less and that if a moratorium were introduced there would be an additional dip of 15-20% in the price of such homes.

Edward Copisarow, chief executive of Children With Leukaemia, said: "This report really gives government the green light it needs to introduce precaution in the UK."