Mice have damaged some 450 kilometres of dykes in Friesland by eating the grass roots, the Telegraaf says on Friday.

This means the grass covering the dykes is dying a slow death which leaves the soil exposed and weakens the water defences.

The Friesland water board is currently assessing the extent of the damage but says no dykes are at risk of breaking.

‘We hope to have a complete picture in March of how much improvement work we need to do,’ a spokesman told the paper.