A number of hypodermic needles were found washed up near Whitlingham Lake on Tuesday.
The needles were spotted by Stephen Gibbons along with some medical gloves near one of the car parks at Whitlingham.
Mr Gibbons claimed that when he informed staff at the visitors centre they said it was nothing new.
The Broads Authority said they have rangers looking for the needles and will keep an eye out for any in the future.
A spokesperson said: 'We are sending rangers down to find the needles and get rid of them. They will also be on the lookout for any medical waste bags to ensure these are cleared up too, if they are the source.
'Our staff and volunteers carry out regular and frequent litter picks at Whitlingham to keep it as tidy and rubbish free as possible and we are grateful that this particular incident has been brought to our attention.'
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