Dutch Scientists are seeking to create mutant flu viruses in an effort to prepare the world for a lethal pandemic.

The idea of creating viral pathogens to be more deadly than current strains has been controversial due to fear of a virus outbreak or it falling into the wrong hands, Thomson Reuters reported.

Dutch scientist Ron Fouchier and Ab Osterhaus, scientists involved with the H7N9 mutation work, said the benefits of this gene mutation research far outweigh the risks.

The experiments are designed to explore H7N9's potential to develop drug resistance and find which genetic mutations might enhance its ability to spread and give scientists the knowledge they need to halt a lethal flu pandemic, according to Fouchier and Osterhaus.

That could be with well-timed new vaccines or other therapies tuned to the pandemic strain's genes.

"We're bracing for what's going to happen next," Osterhaus told Reuters. "If H7N9 becomes easily transmissible between humans, yes, the case fatality ratio may go down a little from where it is now, but we'd still be talking about millions of people dying."

Fouchier, who has already done so-called "gain of function" experiments with another strain of bird flu, H5N1, said we need to get ahead of the game with H7N9 since its pandemic risk would rise "exponentially" if it gained in nature what he aims to give it in the lab - the ability to spread easily among people.

The researcher's efforts have been accused of putting scientific self-interest over security.

Steven Salzberg, professor of medicine and biostatistics from John Hopkins School of Medicine, said Fouchier "is deeply confused about the possible benefits of this work," which Salzberg argues are marginal at best.

"The notion of 'gain of function' research on pathogens is very, very dangerous," he told Reuters.

The H7N9 outbreak, which began in February when the first cases of the flu strain previously unknown in humans emerged, flared up in April and May and dwindled over the summer months.