Key sending Turnbull All Blacks tie

New Zealand Prime Minister John Key is sending Malcolm Turnbull an All Blacks tie to wear in parliament.

The two prime ministers made a bet about the outcome of the Rugby World Cup final, and New Zealand's triumph is Mr Turnbull's loss.

Mr Key says he's posting Mr Turnbull a tie to wear during question time in the Australian parliament next week.

"I'm sending one over. (Mr Turnbull) really wanted an authentic one, so I've taken the liberty of sending a picture of just how good it looks," Mr Key told reporters on Tuesday.

Asked if the tie features a silver fern, Mr Key replied that "it certainly does", before cackling a little.

Mr Turnbull had said it would be "cool" to see Mr Key wearing a gold tie in honour of a Wallabies win.

But after Australia's defeat Mr Turnbull, responding to a Twitter follower who asked if he intended honouring the bet, said: "I am afraid it does bro."