Endoscopy appointments have been suspended at a new hospital unit after rust patches were found on a decontamination machine.
Rust developed on steel parts of casing surrounding the machine, which decontaminates endoscopy equipment after use at St Luke's Hospital, in Market Harborough.
So far, between 10 and 12 patients have been redirected to units in Melton, Hinckley or Loughborough hospitals while the problem is looked at.
Jo Furley, spokeswoman for the unit service, which is provided by Derbyshire Community Health Services NHS Trust, said there was no risk to patients..
"Patients who have had endoscopies recently need not worry," she said. "The rust is on the external casing and not on any of the equipment we use with patients.
"This is a precautionary measure and we apologise for any inconvenience to patients while the service is temporarily out of action.
"We felt it was important to resolve the issue quickly and that has meant asking the makers of the machinery to come in and help us identify why this has happened and make good the rust problems. "Our priority is to reopen the service as quickly as possible.
"Patient safety comes first and while there is no suggestion patients have been put at risk in any way, we have a duty to ensure our equipment is of the highest possible calibre."
An endoscopy involves a tiny fibre-optic camera being inserted into a person's body through the mouth to investigate problems in their bladder, intestine and stomach.
Health campaigner Phil Knowles, from nearby East Langton, applauded the primary care trust for taking action to ensure patients were protected.
However, he added: "I have to ask questions about why a unit which has been open for such little time is already experiencing such problems.
"I have been told it could be shut for up to 11 weeks."
The NHS trust could not tell the Mercury for how long the sessions were expected to be disrupted. A spokesman said they would have a "clearer timescale" once manufacturers had investigated the problem.
The prefabricated hospital unit, which houses the endoscopy service, has been dogged with problems.
It was built in the United Arab Emirates and should have opened in Market Harborough in the summer of 2010.
But problems with design, damage en route, importing the parts for the building and construction saw original contractor Modcon UK sacked last spring.
JH Hallam Contracts took over and completed the unit, which opened in January.
It provides minor operations, scans and other tests for day patients.
