Warning over Europe referendum and assembly campaign clash
A referendum on Europe should be "sufficiently distant" from the assembly elections in May, the Welsh government has said.
It follows speculation the poll on whether the UK should remain in or leave the EU could be held in June.
A Welsh government spokesman said time was needed for the question of Europe to be "separately and fully explored".
Scottish First Minister Nicola Sturgeon said it would be "a mistake" to have it so soon after the devolved elections.
Following the Conservatives' victory in the 2015 general election, there had been speculation an EU referendum could be held on the same day as elections to the Scottish Parliament and assemblies in Wales and Northern Ireland.
A Welsh government spokesman said: "Since the idea of holding an EU referendum this year was first suggested we have consistently called for it to be held on a different date from that for the assembly elections.
"It also needs to be sufficiently distant from them in time so that the implications of the EU question can be separately and fully explored in the referendum campaign."