CANBERRA, Feb. 13 (Xinhua) -- The number of cases of a gonorrhoea superbug in Australia almost tripled in a year, a report has revealed.

The report, released by the National Alert System for Critical Antimicrobial Resistance (CARAlert) on Tuesday, said that its findings were a "warning shot across the bow" for medical experts fighting antibiotic resistance.

There were 742 cases of critically resistant bacteria collected by participating laboratories between April and September 2017, the report said, a 75 percent increase on the 423 cases from the same period in 2016.

A significant rise in the number of cases of Neisseria gonorrhoea, a strain of bacteria responsible for gonorrhoea that is resistant to the antibiotic azithromycin, was largely responsible for the 75 percent increase.

The number of diagnosed cases of the strain rose 182 percent, the report said, from 121 in 2016 to 342 in 2017.

"For the six-month period April 1, 2017 to Sept.30 2017, azithromycin non-susceptible Neisseria gonorrhoea were the most frequently reported Critical Antimicrobial Resistance (CAR) of all CAR types (46.6 percent), followed closely by carbapenemase-producing Enterobacteriaceae (CPE) either alone (41.4 percent) or in combination with ribosomal methyltransferases (RMT) (2.4 percent)," the report said.

"53 percent of CARs were detected from patients in the community (non-hospital patients or aged care home residents.

"There was an increase in the number of CARs reported compared to the same period last year (742 versus 423). This was due almost entirely to increases in azithromycin non-susceptible N. gonorrhoea."

New South Wales (NSW) and Victoria, Australia's two most populous states, accounted for the majority of the resistant gonorrhoea cases with 120 and 160, respectively.

Experts have warned that untreatable gonorrhoea could lead to infertility in women.

A separate report released by New South Wales' Kirby Institute in November 2017 found that the number of Australians diagnosed with gonorrhoea had increased 63 percent in the last five years.

The superbug strain was responsible for a small portion of those cases but experts have warned that it is clearly spreading.