MOSCOW, Nov 28 (Reuters) - The Russian rouble gave up early gains to weaken on Tuesday, easing away from last week's multi-month high as a supportive month-end tax period during which exporters convert foreign exchange revenues, passed

At 1525 GMT, the rouble was 0.5% weaker against the dollar at 89.28, earlier hitting its weakest point since Nov. 20.

It had lost 0.8% to trade at 98.05 versus the euro and shed 0.7% against the yuan to 12.48 .

The market was also assessing the central bank's announcement on Monday that it would resume interventions in the domestic foreign exchange market from January, but using new methodology that analysts said would likely support the rouble.

The rouble has strengthened against the dollar for seven weeks in a row, rebounding from past 100 thanks to reduced capital outflows since President Vladimir Putin introduced capital controls in October.

The rouble may weaken in December, said Alor Broker's Alexei Antonov, as budget payments are finalised and demand for foreign currency from the population picks up ahead of Russia's long New Year holidays.

Month-end tax payments and expectations of another interest rate increase have also been supporting the rouble.

The Bank of Russia, which meets on Dec. 15, raised rates to 15% in late October and has signalled that another increase may be needed.

"It is highly likely that in December the Bank of Russia will still be ready to make a tough step for neutralising inflation risks," said Alfa Bank analysts in a note, with inflation set to comfortably exceed the bank's 4% target.

Brent crude oil, a global benchmark for Russia's main export, was up 1.1% at $80.87 a barrel.

Russian stock indexes were mixed.

The dollar-denominated RTS index was down 0.4% to 1,129.3 points. The rouble-based MOEX Russian index was 0.1% higher at 3,174.3 points.

SPB Exchange's shares dipped lower as it said it would transfer almost a third of clients' funds held in foreign currency to them in roubles, with U.S. sanctions blocking access to the rest of the funds for now.

(Reporting by Reuters; Writing by Alexander Marrow, Editing by Miral Fahmy and Angus MacSwan)