Australian experts have responded to a new study which found men's sperm count has dropped by nearly 60 per cent in the last four decades.

In the meta-analysis of 185 studies, the researchers from the Hebrew University of Jerusalem and the Icahn School of Medicine found a 52.4 percent decrease in sperm concentration and a 59.3 percent decrease in total sperm count.

The research, published in Human Reproduction Update, is an "urgent wake-up call" to explore the causes said the study's lead author.

"If we will not change the ways that we are living and the environment and the chemicals that we are exposed to, I am very worried about what will happen in the future. Eventually we may have a problem, and with reproduction in general, and it may be the extinction of the human species," lead researcher Dr Hagai Levine told the BBC., although other experts said the research and Levine's claims should be treated with caution.