The fees paid to bovine TB valuers in Wales have risen by 154% in the last five years.
The disclosure has promoted Glamorgan milk producer Andrew R T Davies, the leader of the Welsh Conservative Group at the Welsh Assembly, to demand an explanation.
Figures show fees have increased from £158,000 in 2007-08 to £401,000 in 2011-12, even though the total compensation paid out by the Welsh Government has gradually declined, from a high point of almost £24m in 2008-09 to just over £13m last year.
Mr Davies is calling on environment minister John Griffiths to make a ministerial statement on what he describes as a substantial rise.
He said the public was entitled to question why the costs had risen so much.
“Bovine TB represents a huge cost on the farming industry, both in a financial and emotional sense and fair levels of compensation are critical to maintaining industry confidence – but it is concerning to see such a sharp rise in the valuation costs,” said Mr Davies.