SINGAPORE - Mexico's peso extended its two-day winning streak after Donald Trump's answer during the final US presidential debate to whether he would accept US election results received widespread criticism.

The peso rose 0.2 per cent to 18.4925 per US dollar as of 11:38am in Tokyo.

The peso has been dubbed the "Trump Thermometer", because of its sensitivity to Trump's anti-Mexico rhetoric. The rise in the currency suggests markets believe Trump lost the debate.

Asked by moderator Chris Wallace of Fox News whether despite his doubts he would commit to recognizing the result of the November 8 vote no matter what, Trump said: "I'll tell you at the time", eliciting gasps from the audience.

Trump's election struggles have been a boon for peso bulls: the currency is up 6.8 per cent since the first presidential debate on Sept 26, the biggest gain among its major peers, Bloomberg News reported on Thursday.

Asian stocks kept to their positive momentum, propelled more by strong US earnings and oil prices near a 15-month high as the debate ended.

MSCI's broadest index of Asia-Pacific shares outside Japan rose 0.2 per cent. Japan's Nikkei extended gains to 1 per cent. China's CSI 300 reversed earlier gains to fall 0.1 per cent, while Hong Kong's Hang Seng index climbed 0.5 per cent.

"With the polls so heavily in Clinton's favor, markets are priced for her victory," Sean Callow, a senior strategist at Westpac Banking Corp in Sydney, told Bloomberg News. "There probably would only have been a sharp move in markets if Trump had performed extremely well, which wasn't the case."

A Bloomberg Politics national poll on Wednesday showed Clinton expanded her lead over Trump as the pair approach the final presidential debate.