Welsh Secretary Stephen Crabb has written to the First Minister, saying he is disappointed by his response to the St David’s Day agreement and fears momentum will now be lost.
It comes after Carwyn Jones said he felt Wales was not being treated with the same degree of respect as Scotland, adding that the process had been "rushed and unsatisfactory".
I was disappointed to read your reported comments in response to the announcement over the weekend. The package represents a significant movement in Welsh devolution, paving the way for a clearer, stronger and fairer devolution settlement for Wales.
My officials are pressing ahead to ensure a new Wales Bill will be introduced early in the next Parliament. However, I am concerned that momentum may now be lost unless there is strong and positive engagement from the Welsh Government.
David Cameron and Nick Clegg have unveiled proposals for a range of new powers for the Welsh Government and National Assembly.
The UK Government is to announce a range of new powers for the Welsh Assembly in what it calls a 'landmark moment' in devolution