* Nov exports +12.3 pct y/y, imports +17.7 pct
* Natural gas, iron ore imports rise
* Exports of electronics, high-tech products rise (Adds comments from analysts, detail & context)
BEIJING, Dec 8 (Reuters) - China's exports and imports unexpectedly accelerated last month in an encouraging sign for the world's second-biggest economy, though analysts expect growth to continue cooling amid a government crackdown on financial risks and polluting factories.
As global demand has surprised with its strength, consumers have lapped up Chinese goods at a rapid rate this year, giving the economy a boost and providing policy makers room to tighten rules to curb high-risk lending.
Exports in November rose 12.3 percent year-on-year, the fastest pace in eight months, led by strong sales of electronics and high-tech goods, while commodity purchases helped lift imports.
The number beat analysts' forecast of a 5.0 percent increase and compared with 6.9 percent growth in October.
Imports grew 17.7 percent year-on-year in November, the General Administration of Customs said on Friday, also well above expectations of 11.3 percent growth and rising at the fastest pace since September.
The numbers may help to ease concerns of slowing momentum in Asia's economic powerhouse, which had surprised markets with robust growth of nearly 6.9 percent in the first nine months of this year, thanks to a government-led infrastructure spending spree and unexpected strength in exports.
"While we still expect Chinas domestic economy to cool in 2018 on gradually tighter financial policies, the November import data shows that there are upside risks to our China outlook", said Louis Kuijs, head of Asia Economics at Oxford Economics in Hong Kong.
Tighter rules to rein in risks from a rapid build-up in debt and cut pollution have weighed on overall activity since the third quarter.
Besides ramped-up efforts to reduce winter pollution, authorities unveiled fresh regulatory measures last month for the financial sector, clamping down on high-risk lending and halting some dubious infrastructure projects that would swell local governments' debt.
IMPORTS BOUNCE TO TAIL OFF?
Some of China's northern provinces have ordered factories to throttle back or halt output to reduce notoriously thick winter smog.
While the war on pollution had been expected to reduce raw materials imports, Friday's trade numbers showed commodity imports rebounded last month.
China's natural gas imports in November rose to a record as domestic demand surged while crude imports were the second-highest ever, as refiners ramped up output to cash in on strong profits as fuel prices soar.
China's iron ore imports rose in November even as steel mills are cutting output as part of a government drive against pollution as some analysts said traders were stockpiling inventory.
Iron ore imports "were not necessarily just by steel mills but could have been also purchased by traders," said Helen Lau at Argonaut Securities in Hong Kong.
"They're trying to accumulate stocks and will do so maybe through March in anticipation of Chinese mills resuming production when China lifts the winter restrictions."
Steel exports rose from the previous month to 5.35 million tonnes in November, data showed.
The rebound in imports come as China's yuan has fallen 2.8 percent against the dollar since hitting its 2017 peak on Sept. 8.
The latest data showed the country posted a trade surplus of $40.21 billion for the month versus expectations for $35 billion in November after October's $38.185 billion.
Despite the overall strength of the November data, imports could come under pressure as China's economy cools, analysts say.
"Chinese trade looks to have been surprisingly strong last month. We expect exports to continue to perform well in the coming months on the back of strong global demand," Capital Economics China economist Julian Evans-Pritchard wrote in a note.
"However, we are sceptical that the strength of imports can be sustained given that the delayed impact of policy tightening and a cooling property market are set to weigh on Chinese demand for commodities in coming quarters."
(Reporting by Lusha Zhang and Elias Glenn; additional reporting by Winni Zhou in Shanghai; Editing by Shri Navaratnam)