The Australian postal service has apologised for delivering a letter half a century after it was sent from an island in the South Pacific.



A couple from Adelaide found the faded postcard, from the French Polynesian island of Tahiti, resting on their doorstep under a gas bill.  



It bore a postmark of 1966 and was addressed to one "Robert Giorgio," according to the Adelaide Advertiser.



The postcard, which was written by someone named "Chris," reads: "[I am] enjoying myself greatly. The weather is very humid ... I’ll try and drop you a note in England.”



Its stamp cost 13 francs, or around nine pence, and is understood to have been sent to the original owner of the house, whose whereabouts are unknown.



“It took a while to realise it was an old one,” said Tim Duffy, who bought the house 18 months ago with his wife, Claire, and believes it was built by an Italian man in 1963. "Then I checked the post date and it’s 1966.”



He suspects the card may have been sent by someone who was travelling by boat. “It’s fresh enough although it is a bit faded and it’s got some damage to the top left, which looks like a bit of water damage,” he said.  



Mr Duffy handed the letter back to Australia Post, who acknowledged that something had "gone wrong" and issued an apology.



“It is clear something went wrong 50 years ago after the postcard was posted in French Polynesia, and we apologise for the inconvenience,” a spokesman said.



“Australia Post takes great pride in the timely, safe and efficient delivery of mail and we are confident that the vast majority of mail and parcels arrive on time.”



It is not the first time a letter has taken vastly longer than expected to arrive at its destination.



A love letter sent by a British soldier during World War Two was apparently stuck in transit for more than 64 years before it reached RAF Lakenheath in Suffolk.



The missive was penned on Red Cross-headed paper by Serviceman Charles Fleming to a woman identified only as "my dearest" on March 20 1945.



Neither of them have come forward to claim the letter since its discovery.