The most popular web browsers detect and block phishing attacks at least 90 percent of the time with Google's Chrome marginally the best performer, an NSS Labs report has found.

The testing firm pitted Google Chrome 21, Mozilla Firefox 15, Apple Safari 5 and Internet Explorer 10 (on Windows 8) against 2,291 unique phishing URLs in a realtime test, finding that Chrome reached a 94 percent catch rate over a ten-day period.

Internet Explorer 10 (the only browser not to use Google's SafeBrowsing API) came second on 92 percent, Safari third on 91 percent with Firefox in last place on 90 percent.

Conclusion: the browsers are very similar in their basic ability to block phishing sites and hugely improved on the pretty poor performance - around 47 percent - found to afflict the same browsers during a similar assessment by NSS Labs in 2009.

They did vary far more when it came to the average time to block URLs, with Firefox and Safari hitting 79.2 percent and 76.9 percent respectively for 'zero hour' detection of phishing attacks leaving IE10 and Chrome lagging on only 55.9 percent and 53.2 percent.

Second conclusion: while browsers are nearly identical in their ability to spot phishing URLs, some take longer to reach that performance than others. Firefox was also the quickest to add a phishing site to its block list, doing so in 2.35 hours compared to over five hours for the others.

Three of the four, Firefox, Chrome and Safari, use Google's SafeBrowsing API while IE10 uses Microsoft's own SmartScreen.

"Looking back to 2009 when the best browser blocked 83% and the worst a mere 2%, it is obvious that all of the tested vendors have made significant strides in their abilities to block phishing attacks," note the researchers.

"Going forward, the challenge will be to bring down the response time, especially for targeted brands with the largest consumer bases."

The firm makes clear that phishing websites are only one of the malevolent forces that browsers must defend against; a fuller picture must also take into account of threats such as drive-by malware.

NSS Labs carried out such a test in October and found much less impressive results for some browsers.

According to Anti-Phishing World Group (APWG) figures, the number of unique phishing websites has hovered around 50,000 per month during 2012, even if the average lifespan of each has decreased markedly since 2009 to just under a day.