Binmen say they are already struggling to cope with their workload and have been kept in the dark about how the new scheme – due to come in next month – will operate.

However, North Lanarkshire Counci insisted it is well prepared for the launch.

Ken Wilson, head of land services, said: "We have been planning the implementation of this scheme for almost a year and continue to monitor performance and plan for every eventuality – including staff requirements.

"There are no concerns about the staffing levels required to deliver the new collection scheme, now or in the future. Some changes to the way the cleansing service is managed will be made in coming months, but not before the new system is implemented.

"Plans are in place to ensure those changes do not affect the efficient running of bin collections."

The council is aiming to increase the amount of rubbish it recycles by switching to the system which has been running in South Lanarkshire for many years.

There will be no longer be a weekly uplift of ordinary household waste.

Instead householders will put out that bin one week and a new blue bin containing paper, tin and plastic items the next.

The council sent leaflets to thousands of homes, but last month 48 roadshows outlining the scheme were branded a waste of money and officials' time.

One refuse worker based at the council's Albert Street depot in Motherwell claimed that while the department has spent money on leaflet drops and roadshows staff have not been given sufficient information about the system.

The worker, who asked not to be named, said: "I don't think the department is ready for this. We are struggling just now to man bin vehicles, but at least when we need back-up we can call on street cleaners and litter pickers.

"But they are to be transferred to another department so we'll no longer be able to use them."

The worker claimed garden waste, which is already collected separately, is being contaminated because staff shortages mean drivers are asked to collect it alongside household waste.

He added: "That means instead of the garden stuff being treated separately the entire load goes to landfill, defeating the purpose.

"What's more, some people are putting stuff in the new blue bins that can't yet be recycled which means more contamination. The situation is a shambles."

Council SNP group leader Richard Lyle said he is aware of drivers' concerns and believes morale to be at "rock bottom". He plans to raise the issue at a forthcoming council meeting.

He said: "These allegations don't surprise me as I believe the council has bitten off more than it can chew. I fear there will be disquiet among the workforce when this system comes in."

The council has already introduced the new system in other parts of North Lanarkshire and Mr Wilson said: "Initial results are extremely positive. Presentation rates are very high and levels of contamination very low. We have already increased the amount of waste sent for recycling from 90 tonnes per week to more than 560 tonnes."

Mr Wilson said the council anticipated some households would start using the new system too soon.

He added: "A very small number of households have been doing that, but special collection arrangements are in place and all the materials in them will be sorted and presented for recycling – none will be sent to landfill.

''Most households are still using their blue bins for paper only, and I would stress that they should continue to do so until the new scheme comes in.

"The fact that so few households have mistaken the implementation date shows the success of our communication campaign."