A move to introduce wheelie bins for rubbish collection in parts of Birmingham is in danger of splitting the city council's ruling Conservative-Liberal Democrat coalition.

Constituencies will be encouraged to run pilot projects, using wheeled bins instead of plastic sacks to collect recyclable material and garden waste, if the findings of a scrutiny committee are accepted.

But the proposal has proved controversial, with Tory committee members publishing their own minority report condemning wheelie bins as expensive and unlikely to increase recycling rates.

Martin Mullaney, the Liberal Democrat chairman of the transportation and street services scrutiny committee, said he respected the views of Tory councillors Robert Alden and Tim Huxtable, but hoped the council cabinet would not stand in the way of constituency committees who wished to test wheelie bins.

Coun Mullaney (Lib Dem Moseley & Kings Heath) added: "We don't always reach a point where we agree entirely with one another. In this instance this is the case and we have a position where we have not been able to present a united report. I see this in no way as a failing."

The committee rejected using wheelie bins for domestic waste, on the grounds that the size of 240-litre bins would encourage people to put out more rubbish.

But the same argument meant the presence of wheeled bins would encourage people to recycle and help Birmingham to reach a target of recycling 34 per cent of all household waste by 2012, the report adds.

The document, endorsed by Liberal Democrat and Labour members of the committee, concludes: "To simply introduce a new system of wheeled bin collection across the city could be questionable in terms of whether it would raise recycling rates.

"We are asking constituencies in the first instance to propose areas where a recycling pilot with wheeled bins could work. These should be planned in close consultation with elected members."

Cabinet transportation member Len Gregory is unlikely to co-operate with wheelie bin experiments.

Coun Gregory (Con Billesley), in a written response to the scrutiny committee, said pilot schemes would require substantial up-front capital investment and he did not believe any savings would be delivered in the long term.

Smaller rounds for wheelie bins meant less rubbish would be collected and the overall cost would rise. The Conservative minority report said there were "serious concerns" about the committee's conclusions and warned that wheelie bins would simply replace one container with another rather than actively increasing recycling.

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* It is being suggested pilots could be based on refuse collection rounds of 7,500 properties, compared with an average 10,000 households per black sack round.

* Each household could get two wheeled bins, one for green waste and a smaller one for plastic, glass, cans, paper and cardboard.

* At a cost of £15 for each 240-litre bin compared with £1.10 per household for a year's supply of refuse sacks, wheelie bins would prove expensive in the short term.

* By the second year of a pilot project the cost of providing wheelie bins for 30,000 households would be £858,000 a year, against £951,000 for plastic sacks. Initial capital costs would be recovered within six years.

* The report rejected a move to fort-nightly collection of non-recyclable household rubbish.