An Australian collector has set a new world record after paying a small fortune for one of the world's rarest and most-mysterious stamps.

The collector bought the strip of four 1948 Gandhi 10-rupee purple-brown 'SERVICE' stamps for $855,000 last week.

A mystery Australian collector paid $855,000 for these four stamps at auction last week.

Only 13 of the stamps exist in private collections around the world.

The price paid is a new high-water mark for Indian stamps. The most ever paid for a stamp was the $US9.5 million paid at auction for an 1856 British Guiana 1 cent magenta.