Australian banks' lending to Chinese borrowers has soared by 75 per cent in a year, as the industry rushes to lift its exposure to Asia's powerhouse economy.

The value of loans to Chinese borrowers on the books of Australian banks swelled by $US12.3 billion to $US28.7 billion during the year to September, figures from the Bank for International Settlements show.

The RBA is wary of rapid growth.

China now rivals Singapore as a key foreign market for Australian bank loans, trailing only New Zealand, Britain and the US.

Hong Kong - a critical gateway for institutional lending into China - is also playing an increasingly important role, with exposure of $US20 billion.