Horizons Regional Council is seeking comment from various organisations about how well they think the One Plan is being implemented.
Letters have been sent to a range of groups including in the agricultural and environmental sectors, district councils and iwi, inviting them to respond.
It will be an ongoing evaluation which will first focus on nutrient management rules.
The One Plan, adopted in 2014, combined the regional council's policy statement, regional coastal plan and regional plan into one document and for the first time required intensive farming operations to have consent.
Horizons policy and strategy manager Tom Bowen said it had asked for feedback from organisations which would then be reported to council in August.