* Rouble has tumbled more than 40 percent vs dollar in 2014
* Central bank seen intervening on Friday to halt slide
* Rosneft's dollar buying adds pressure - traders (Updates prices, adds extension of FX swap limit)
By Vladimir Abramov and Vladimir Soldatkin
MOSCOW, Dec 12 (Reuters) - The Russian rouble dropped to a new low of almost 58 to the dollar, continuing a slide that traders said led the central bank to intervene in the market on Friday after a rate hike failed to break the currency's fall.
At 1450 GMT, the rouble was around 1.7 percent weaker against the dollar at 57.36 and down 2.4 percent to trade at 71.55 versus the euro.
Dollar-denominated Russian stocks also dropped, following the weaker currency and lower oil prices.
The rouble has lost more than 40 percent against the dollar since the beginning of the year, hurt by a slide in oil prices and risk aversion to Russian assets fuelled by Russia's standoff with the West over the crisis in Ukraine.
Russia's central bank raised its main lending rate by one percentage point on Thursday but failed to stop the rouble's slide or lift the gloom over the economy.
Some traders said the bank had intervened on Friday as the rouble approached 58 to the dollar. It hit a high of 57.98 on the Moscow Exchange.
"This, without doubt, was the central bank. ... I believe it went out to defend the 58 rouble mark and sold some $700 million in a short time," said Aleksei Vorobyov, head of forex operations at Vozrozhdenie bank.
Russia's central bank said on Friday it had conducted 11.18 billion roubles ($197.44 million) worth of forex market interventions on Dec. 10. That followed $348 million in interventions on Dec. 9 and around $4.5 billion in interventions last week, despite the bank floating the rouble in November.
Traders said the rouble could also be hurt by expected dollar buying by Russia's top oil producer, Rosneft, which sold 625 billion roubles ($11 billion) worth of bonds on Thursday.
Comments from the central bank that it would keep limiting rouble liquidity via its foreign-exchange swap operations in a bid to stabilise the currency market did little to support the rouble.
The RTS index fell 1.9 percent to 808 points but the MICEX index was 1.1 percent higher at 1,471 points, conversely helped by the weaker rouble.
The price of oil, which together with sales of natural gas accounts for half of Russia's federal budget revenues, has reached a new 5 1/2-year low due to persistent concerns over a global supply glut and a bearish outlook for demand.
Shares of indebted miner Mechel were among firms leading losses on the Moscow Exchange, falling more than 6 percent amid a battle over debt claims. ($1 = 57.4920 roubles)