Planning rules to protect new buildings from climate change-related flooding have been put on hold until June 2023, a week before they were meant to start.
Welsh ministers have delayed changes due to come into force on 1 December after complaints from some councils.
In future, developers in Wales must consider the risk of floods and coastal erosion due to global warming.
Latest projections show a growing proportion of Wales is at risk of flooding from rivers and the sea.
In September, a set of maps was unveiled to show current risk levels, as well as the risk posed by climate change.
It was part of an update to a planning policy called Technical Advice Note (Tan) 15 that would help authorities decide whether to approve applications to build.
But, after some raised concerns, Climate Change Minister Julie James said she would suspend the new Tan 15 until 1 June 2023 "to allow local planning authorities to fully consider the impact of the climate change projections".
The maps show "some significant increases in the extent of the highest risk flood zones including in some of our city and town centres", she said.
The statement came on the day she launched a major consultation into adapting the planning system to limit the number of second homes and holiday lets.
What do local councils say?
They delay was welcomed by the Welsh Local Government Association, which said it "granted more time to ensure Tan 15 is implemented and that it supports sustainable developments that grow our economy and create jobs".
It said in a statement: "This extra time will be used to ensure flood maps have been fully reviewed and the appropriate Tan wording agreed, and that these are supported by robust plans to address flood risk and protect our communities.
"Councils will continue to carry out detailed flood consequence assessments over the next 12 months based on the new maps, and we look forward to working with the Welsh government to develop an agreed pipeline of flood mitigation measures."