Fewer councillors for Wales pledge by Leighton Andrews
Wales will have "fewer council leaders, fewer chief executives, fewer council cabinets and fewer councillors", the public services minister has promised.
Leighton Andrews said that if councils do not come up with proposals to merge voluntarily, mergers will be imposed.
He also warned voluntary proposals would not be accepted if they were neither "viable nor sustainable".
In January, the Williams Commission recommended the current 22 Welsh councils should be cut to 10, 11 or 12.
Councils have been asked to submit merger plans by the end of November.
Mr Andrews told BBC Wales he wanted to see "sensible mergers".
Speaking to The Wales Report, Mr Andrews said he is not certain that local authorities accept the need for radical change.
"That's why I've made it very clear that if we don't get the voluntary mergers we will take action", he warned.
He said the current number of councillors costs Wales more than £21m per year.
The Williams Commission proposals on local government reform would cut that bill by a quarter to around £15m, he claimed.
There are 1,264 county councillors in Wales - around 40 more than in Scotland, which has a bigger population.
Mr Andrews claimed there were "senior people" in the Labour Party who think there should be six or seven local authorities, halving the cost to below £10m per year.
"We understand these are very difficult times for people out there, these are very difficult times for people to be councillors, but the proposals that we will come forward with mean fewer council leaders, fewer chief executives, fewer council cabinets and fewer councillors", he added.
The Wales Report is on BBC One Wales at 22:35 BST on Wednesday 15 October