A watchdog group set up to monitor waste charges says it has not found evidence of "price gouging" with the phasing out of flat fee collections.

Frank Conway, Chair of the Price Monitoring Group, told an Oireachtas Committee that "while fluctuations in prices and service offerings have been observed, the overall trend is relative price stability".

However Mr Conway said some waste companies are introducing or increasing costs for green bin waste since China announced a restriction on the intake of recyclable waste.

Frank O'Donoghue from the Department of Communications, Climate Change and Environment said that the value of recyclable waste is now "zero or negligible" and that it is costing operators to move it.

He said that contamination of green waste which can affect an entire load is still running at 36% in some parts of the country and "can't continue".

Deputy Brian Stanley of Sinn Féin asked if a franchise system could be introduced for waste collection companies by local authorities.

Mr O'Donoghue said the Government will consider this pending completion of studies on the waste market.

Chairwoman Hildegarde Naughten of Fine Gael asked if the Price Monitoring Group needed more powers to make waste companies pricing structure more transparent.

Mr Conway said there has been difficulty for customers getting information over the phone and that the group has called on operators to provide better training for staff.

He said there are nine different pricing models with the most popular being a service charge including a weight allowance plus per kilogramme charge for excess.

The group was set up to monitor the cost of residential waste collection as the 'flat-rate structure' was phased out as a way of incentivising the prevention and segregation of household waste.

The group has compiled seven months of data and is due to finish its work in July.