Aug 15 (Reuters) - Copper prices rose on Tuesday from a six-week low hit in the previous session, on expectations of improving demand as top metals consumer China cut policy rates, and as a softer dollar made greenback-priced metals cheaper to holders of other currencies.

Three-month copper on the London Metal Exchange advanced 0.6% to $8,338 per metric ton by 0605 GMT, on track for its first session of gain in four.

The dollar index eased from a five-week high hit in the previous session.

China's central bank unexpectedly cut key policy rates for a second time in three months, in a sign that authorities are ramping up monetary easing efforts to boost a sputtering economic recovery.

The most-traded September copper contract on the Shanghai Futures Exchange rose 0.8% to 68,530 yuan ($9,413.07) per metric ton.

But gains were capped as property investment in China extended its fall for the 17th consecutive month in July, and home sales slumped amid a deepening debt crisis, especially at real estate giant Country Garden.

"PBOC (People's Bank of China) cut rates to boost market... to counter the negative retail data. I think we've reached support, (prices) can't fall anymore," said a metals trader.

LME aluminium increased 0.6% to $2,159 per metric ton, nickel rose 0.6% to $20,210, zinc climbed 0.7% to $2,365.50, lead edged up 0.3% at $2,103, while tin advanced 0.9% to $25,545.

SHFE aluminium rose 0.6% to 18,415 yuan per metric ton, while nickel fell 0.3% to 164,440 yuan, zinc dipped 0.1% to 20,420 yuan, lead rose 0.1% to 15,920 yuan, and tin lost 1.5% to 214,410 yuan.

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($1 = 7.2803 yuan) (Reporting by Mai Nguyen in Hanoi; Editing by Subhranshu Sahu and Eileen Soreng)