It was announced in February that the veteran Australian, who led England to the World Cup final last year, had signed a new deal until the end of 2019.
However, with his side having won the ongoing series against New Zealand with a game to spare, some players have already said they would love to see the coach lead them into the 2021 World Cup.
Bennett, of course, would be 71 by then and it remains to be seen what his own plans are but Sinfield admits nothing is ruled out from the RFL’s side.
“We’ve not opened talks yet,” he said. “On the back of the World Cup we agreed we’d take it two years at a time.
“At that stage, I think we both weren’t sure what this next couple of years would bring.
“I have to say I’m delighted in what he’s done – the belief and confidence he’s put in the players, the environment he’s created there and the value of the badge is so much greater than it’s been for a long, long time.
“I think to jump into anything now would be pretty foolish.
“He’s probably got a few other things that are going on with him back home at this moment in time.
“But I’ve no doubt I’ll sit down with him in the next few days to have a chat about the future.
“We already have had some brief conversations but we’ll see. There’s nothing nailed on. The contract finishes at the end of next year and, as things stand, he’ll start his contract with Souths at that point and we’ll see.”
South Sydney announced last week that the Queenslander – rated by many as the greatest rugby league coach of all time – would take over there as their head coach in 2020.
Bennett is currently still contracted as Brisbane Broncos coach for 2019 but, with current Souths chief Anthony Siebold due to replace him in 2020, it is understood talks are under way for the essential swap to be expedited in readiness for next term.
Souths have intimated they would not stand in Bennett’s way if he wanted to continue working with England once he has taken over at Redfearn.
Sinfield, meanwhile, is delighted with how the series has gone with impressive wins in Hull and Liverpool – both televised live on the BBC – producing a feel-good factor about the national side.
“It’s been brilliant,” he said, ahead of Sunday’s third and final Test at Elland Road. I’ve been delighted with the last two years I must say – I think what we did in the World Cup was pretty special – and to be able to continue that, bring the (England) Knights back and send them off to PNG on a wow of a trip and great experience.
“If you look at the squad and the quality of player we’re missing at this time – big Sam (Burgess), Luke Gale, Kallum Watkins, Ryan Hall, James Roby, Alex Walmsley, Ben Currie – they are all top, world-class players.
“I don’t think we would have coped with that before but we are in a really good place and I have to give a lot of credit to Wayne.”