John Key dons a Wallabies jersey after losing a bet on Saturday's rugby test with CNBC channel anchor Oriel Morrison.

Prime Minister John Key's dream run of bets backing Kiwi sports team has come to an end.

On Sunday he (mostly) honoured the sporting wager with a CNBC anchorwoman Oriel Morison and donned a Wallabies jersey after the All Black's 27-19 defeat at the hands of Australia on Saturday.

Key wore the jersey but posed partly shielded by a Singapore scarf at celebrations of the city-state's 50th anniversary of independence on Sunday.

He had made similar bets with former Australian prime ministers Kevin Rudd and Julia Gillard, but was on the winning side both times.