A growing practice that allows academics submitting papers to peer-reviewed journals to name individuals they would prefer not to be used as reviewers has come under criticism for undermining the independence of the system.
Automated web systems used by academic publishers also allow those submitting a research paper to name preferred reviewers.
"It seems to me that both options are an extraordinary breach of the independence of the peer-review system," said Terry Cannon, reader in development studies at the University of Greenwich, who submitted a paper to Natural Hazards, published by Springer.
A Springer spokeswoman said the practice was "quite common". "Authors are asked to give reasons for their suggestions - and in many cases there are good and perfectly legitimate reasons for such suggestions. Of course, the scientific editors do not have to follow these suggestions, and in fact they frequently don't," she added. "We do not think this constitutes a breach of the independence of peer review."
Adrian Mulligan, associate director in research and academic relations at the publisher Elsevier said: "The question is how the information is used. It's not as though the editor will always go with the recommendation; it's one consideration among many. The option is often there to reassure the author that a competitor will not see the research in advance of publication."
Stuart Penkett, an environmental physicist at the University of East Anglia who is on the advisory board of Atmospheric Chemistry and Physics, said he was not aware that it was possible to suggest unsuitable reviewers. "Unfortunately some reviewers do express very negative opinions, sometimes for wrong reasons."
Nature Journals' guide to publication policies says: "Authors are welcome to suggest suitable independent reviewers, but these suggestions may not be followed. They may also request that the journal excludes one or two individuals or laboratories. The journal sympathetically considers such exclusion requests and usually honours them, but the editor's decision on the choice of peer reviewers is final."
Harvey Markovitch, chairman of the Committee of Publication Ethics, said the practice was "neither remarkable not reprehensible". Research had found that recommended reviewers were more likely to suggest acceptance of a paper.
"But whether or not to accept is an editorial decision, the reviewer does not make that decision," he said.