A plan to move the sterilisation of surgical equipment out of hospitals is "a recipe for chaos", a group of surgeons has said.
Equipment must be sterile to prevent infection
The government wants instruments to be cleaned at about 50 new "super centres" across England and Wales, each serving all hospitals in a region.
But the British Orthopaedic Association (BOA) says this could delay operations.
Ministers insist centralisation is needed to ensure hospitals meet new standards for cleanliness.
Some NHS Trusts have already closed older sterilisation units and moved cleaning to new purpose-built sites.
But surgeon Andrew Thomas, spokesman for the BOA, told BBC Radio 4's Today programme that he fears the policy is "a recipe for chaos".
And he said the BOA has contacted the National Audit Office to query whether centralising sterilisation services represented value for money for the NHS.
In January, new figures obtained by Conservative MP Grant Shapps showed there had been a big increase in the number of operations cancelled due to a lack of sterile surgical instruments.
A total of 1,765 operations were cancelled in 2005/06 - up 40% from 1,252 in 2002/03.