* Nov Iran crude imports at 1.7 mln T vs 395,132 T year ago

* Hyundai Chemical splitter boosts Iranian condensate demand

* Jan-Nov crude imports from Iran up 126.4 pct y/y

* Total Nov crude imports at 12.26 mln T, up 12 pct y/y

By Jane Chung

SEOUL, Dec 15 (Reuters) - South Korea's Iranian crude oil imports rose more than fourfold in November from a year earlier and nearly doubled from the previous month as Hyundai Chemical started its new condensate splitter, while Tehran continued to increase its output to pre-sanction levels.

The world's fifth-largest crude importer imported 1.73 million tonnes of Iranian crude last month, or 423,020 barrels per day (bpd), compared with 395,132 tonnes during the same month a year earlier and 902,987 tonnes in the previous month, customs office data showed on Thursday.

Hyundai Chemical, a joint venture between Hyundai Oilbank Co Ltd INPTVH.UL and Lotte Chemical 011170.KS , completed its 130,000 bpd condensate splitter in Daesan and began operation last month. urn:newsml:reuters.com:*:nL4N1DG1PG

"The increase in November Iran crude imports was boosted by the start-up of Hyundai Chemical's condensate splitter as it brought in Iranian condensate to run the splitter," an energy ministry official said.

South Korea's crude oil import data usually includes condensate, but it does not provide a breakdown.

For the first 11 months of 2016, Seoul shipped in 12.45 million tonnes of Iranian crude, or 273,193 bpd, more than double the 5.5 million tonnes imported during the same period a year earlier.

Iran, one of the member countries of the Organization of the Petroleum Exporting Countries (OPEC), had been initially hesitant to cut its oil production, but as Saudi Arabia, OPEC's largest producer, agreed to bear the lion's share of the cuts, OPEC reached a landmark deal to reduce oil output last month. urn:newsml:reuters.com:*:nL81DW115

Overall, Asia's fourth-largest economy imported 12.26 million tonnes of crude oil last month, or nearly 3 million bpd, up 12 percent from 10.94 million tonnes a year ago, according to the customs data.

South Korea imported 130.7 million tonnes of crude in the January-November period of 2016, or 2.87 million bpd, up 5 percent from 124.43 million tonnes a year ago.

Final data for November crude oil imports will be released by state-run Korea National Oil Corp later this month.

(Reporting by Jane Chung; Editing by Amrutha Gayathri) ((jane.chung@thomsonreuters.com; +82 2 3704 5667; Reuters Messaging: jane.chung.thomsonreuters.com@reuters.net))