UPDATE 1-OPEC relaxed on prospect of early 2013 stockbuild

* Says current oil price acceptable to producers

* Members being asked to stick to 30 mln bpd target

* Sees OPEC spare capacity at 3-4 million bpd

(Adds quotes, details)

VIENNA, Dec 13 (Reuters) - OPEC is relaxed about the prospect of rising inventories in the first half of next year, the group's secretary general said on Thursday, so long as oil prices avoid extreme moves from their current acceptable level.

The Organization of the Petroleum Exporting Countries agreed to maintain its oil output target of 30 million barrels per day (bpd) at a meeting on Wednesday, a production level the group exceeded in November by 800,000 bpd.

OPEC's own forecasts show demand for the group's oil will average 29.25 million bpd in the first half of 2013, implying inventories could build up should the group keep pumping oil at November's rate, potentially weighing on prices.

Secretary-General Abdullah al-Badri, whose term was extended for another year at Wednesday's meeting, told reporters at a briefing this was not a concern.

"There is a stock build up, this is normal," he said, adding that in the third and fourth quarters of the year, inventories tend to draw down. "OPEC is concerned only when they see two extremes - extreme price too high or extreme price too low. This is where we wil get concerned."

"I think this price is acceptable to producers and consumers," he said of the current oil price around $109 a barrel.

OPEC did not call explicity in its statement released after Wednesday's meeting for member countries to comply more closely with the 30 million bpd target, but Badri said they were being asked to cut back.

"We decided to go back to the 30 million barrels per day and we asked member-countries that they should adhere to their designated number," he said.

OPEC has been pumping more than the 30 million bpd target all year, and Badri said the oil the group was producing above forecast demand for its crude may be heading into inventories outside OECD industrialised countries.

"Maybe the other barrels, they go to non-OECD stocks. These stocks are growing very fast."

A drop in OPEC's production in the last few months has increased the level of spare production capacity among members of the group.

"Right now, it's about 3 to 4 million bpd, which is fine," Badri said.

(Editing by William Hardy, Vienna OPEC newsroom)