Jun 21st, 2016

Maroons great Johnathan Thurston has given strong indication of his impending retirement. (AAP)

Jun 21st, 2016

North Queensland Cowboys superstar Johnathan Thurston has shocked NRL fans by indicating he will hang up the boots at the end of 2018.

But the 33-year-old said leaving the Maroons would be the "hardest" decision of his glittering career.

The veteran said he told the club he would "be stepping down" from representative footy after 2017 with an eye on a full retirement a year later.

"I can't see myself going around in 2019," Thurston told the Courier Mail.

"I have indicated to the club I will be stepping down after the World Cup.

"If I have the last year in 2018 I want to make sure I am enjoying it."

However, Thurston, who plays his 35th consecutive Origin match at Suncorp Stadium, admitted playing side-by-side his Maroon teammates almost changed his mind.

"After the first game of the series though I have started to have second thoughts about that," he said.

"It will be the hardest (decision)."