The 50-year-old Labour politician was dismissed from the Welsh Government's Cabinet after asking civil servants for private financial information on rival Assembly Members.
He asked for details of farm subsidies paid to opposition politicians including Welsh Tory leader Andrew RT Davies, Welsh Liberal Democrat chief Kirsty Williams and Plaid Cymru's Llyr Huws Gruffydd.
First Minister Carwyn Jones said: "Communications between the Minister for Natural Resources and Food (Mr Davies) and civil servants has been drawn to my attention.
"I believe these requests were poorly judged, inappropriate and ... unacceptable."
Mr Davies's departure from his Welsh Government post comes less than a week after he apologised to AMs in a separate row about him breaking the Ministerial Code of Conduct.
It came after he lobbied an environment body for the new Circuit of Wales race track while still a Welsh Government minister.
Rival parties welcomed the decision to relieve Mr Davies of his Government duties - but said it should have come sooner.