An estimated 80,000 eels will need to be rehomed when new sewage ponds are completed outside Masterton.
The eels are resident in the old sewage ponds, and must be shifted to the new ponds as a switch to the new sewage treatment plant approaches.
Masterton District Council special projects manager Ian Steer has been charged with helping the eels squirm across dry land to their new home.
"What we plan to do is slowly wind back the flow into the old ponds over three to six months and with the aerators off the oxygen levels will drop," Mr Steer said.
"That should encourage the eels to migrate over land to the new ponds and take up residence there."