All Blacks' Sonny Bill Williams hints 2019 could be last year with the Blues

New Zealand centre has previously hinted at a return to rugby league or taking up a coaching position at the end of the Rugby World Cup in November

New Zealand centre Sonny Bill Williams, centre, has indicated that this year could be his last with the Auckland Blues. AFP

Sonny Bill Williams said this season could be his last with the Auckland Blues as the All Blacks centre weighs up his options after the World Cup in Japan later this year.

Williams, a two-time Rugby World Cup winner with New Zealand, will be a free agent following the global showpiece in November with the 33 year old a near-certainty to be named in Steve Hansen's squad as they chase an unprecedented third straight title.

Williams, arguably the most successful dual-code player ever, has previously hinted at a return to rugby league at the end of his Blues deal or even hanging up his boots to pursue a coaching role.

Those outcomes were given more weight on Tuesday when Williams told reporters at a training camp for the Blues that this year could be his last with the Super Rugby franchise.

"It could be, bro, it could be," he told the New Zealand Herald when asked if it could be his final season at his hometown club.

"If I did finish at the end of the year, as long as I competed every day and put my best foot forward as a person and a player I'll be happy."

Williams has been an automatic pick for All Blacks selection when fit but has been severely hampered by injuries in recent seasons.

He tore his Achilles while playing rugby sevens at the Rio Olympics in 2016 and has battled with wrist, knee, hand and shoulder injuries since.

The inside centre, however, said that he was now back at full fitness and would be available for selection for the Blues for their opening Super Rugby match with the Canterbury Crusaders at Eden Park on February. 16.

"For the last two years I've been so methodical with my planning and preparation," he said. "Every off-season: 'A, B, C, D and I'm going to get to E'.

"It starts here with the Blues. I want us to have a successful year. I want the boys to succeed."

Competition for places in the Blues midfielder has intensified with the return of fellow World Cup winning centre Ma'a Nonu back in New Zealand rugby with the Auckland-based franchise after three seasons in France following the 2015 tournament victory.

Both prefer to play in the No 12 jersey, but Williams said they were quite comfortable in the same midfield if required.

"We've always had a good friendship. It's no secret that we've always competed for the same position, we're out here competing as you can see but we're laughing and bringing out the best in each other as well," he added.

"I feel like some of the best games we've played for the All Blacks have been together. I don't think that will be an issue."