A council plan to spend £730,000 on smaller wheelie bins to encourage people to recycle more has been condemned as "barmy".
Neath Port Talbot council's plans are a waste of public money, South Wales West AM Peter Black has said.
But the council defended the move as recycling rates in a pilot area have improved where households have been given smaller bins for general waste.
Some homes have already seen their bin size reduce from 240 to 140 litres.
An internal council report seen by BBC Wales estimates that it would cost around £730,000 to extend it across the county borough.
The Welsh government is providing some of the funding as it has made more than £11m available to councils for projects encouraging recycling over the next three years.
It recommends councils consider reducing wheelie bin size which Neath Port Talbot council has agreed to do.
Last year the Welsh government announced councils had successfully met the target it set of recycling more than half of the waste they collect.
The ultimate aim is for Wales to recycle 70% of its rubbish by 2025 and to become a zero waste nation by 2050.
Neath Port Talbot council says reducing the size of wheelie bins will help it meet targets.
Chief executive Steve Phillips told BBC Wales the council had so far spent around £150,000 on bins and the £700,000 was the total figure of the recycling programme over several years.
He said: "A couple of years ago we found ourselves at the bottom of the all-Wales recycling league table.
"We faced the serious prospect of fines from the Welsh government.
"We put in place a strategy which included the roll-out of smaller wheelie bins to address that position.
"We've managed to secure a substantial improvement in our performance and avoid the Welsh government fines."
Welsh Liberal Democrat AM Peter Black says it is a waste of money and could encourage people to dump rubbish.
"This scheme is barmy, a complete waste of £730,000 of the public's money, and comes at a time when the council is planning to cut a host of other important services which will impact upon local communities," he said.
"All that will happen is more fly-tipping and litter which the council will have to spend money clearing up.
"Nobody is arguing about the need to put up recycling, but Neath Port Talbot's approach is all compulsion, and no carrot."
Neath Port Talbot council's recycling guide says it provides householders with:
- a green box for recycling glass bottles and jars as well as tins
- separate bags for plastic packaging, papers and magazines, cardboard and cartons, mixed textiles and garden waste
- a caddy for food waste
- a wheelie bin for non recyclable general waste which it aims to replace with smaller-sized bins.