Environmental body Natural Resources Wales cost £17m
Setting up environmental body Natural Resources Wales (NRW) cost taxpayers £17m, say the Welsh Conservatives.
Shadow rural affairs minister Antoinette Sandbach said that includes almost £5m in pay-offs to 123 staff.
It follows the merger of the Environment Agency, Countryside Council for Wales and Forestry Commission to form NRW in April.
The Welsh government says it expects the new body to save £127m over the next decade.
But Ms Sandbach, an assembly member in north Wales, challenged the use of public money.
She said: "I have consistently sought to scrutinise the cost of setting up this single body but we have had to drag out the figures very slowly from the Minister - and now we can see why.
"When this merger was first proposed, the business case went unpublished and our calls for clarity went unanswered.
"I challenge the minister to explain how NRW is delivering a better service for the people of Wales.
"All I can see is a very large bill, which we're all having to pick up at a time when there are ever-increasing demands on the budget."
NRW confirmed that 123 staff in the new merged body agreed to take voluntary redundancy, with the majority leaving at the end of December.
It said the total cost of the redundancy scheme was £4.8m, and could rise to £5m if a small number of other staff take up offers of redundancy.
But the body stressed that staff savings of £800,000 would be made in this financial year, and £4.2m in 2014-2015.
A spokesperson said it meant the redundancy scheme would "have paid for itself in 15 months".
"The savings after this of more than £4m every year will be re-invested into important work like reducing flood risk, maintaining a good supply of timber for the industry and improving the environment for people, the economy and wildlife," said the spokesperson.
However, figures obtained by Ms Sandbach show that the other costs for setting up the new body included £10.7m for new information technology systems, more than £1m on legal advice, and £242,000 on rebranding costs.
"Surely there are better uses of £17m of public money," added Ms Sandbach.
Responding to the figures revealed by the AM, the Welsh government insisted that the new body would deliver savings.
"As well as playing a crucial role in the way we manage our natural resources, we expect NRW to deliver gross cash savings of £127 million over the next 10 years," said a spokesperson.