Jarryd Hayne says he is not in "sevens shape" and doesn't know if he will be in time for the Rio Olympics, but the 28-year-old insists he will have no regrets if he fails to make the Fiji squad.

Hayne joined his new teammates at their training camp in Pacific Harbour on Monday, with a month to prove he belongs among some of the best players on the sevens circuit.

There are many trying to predict what he'll do after his sevens stint but Hayne says "they've got no idea because I've got no idea".

He has never ruled out a return to Parramatta but when asked how high on the priority list it was, there remains questions as to whether he will wear the blue and gold again.

"If that's where I believe I need to be or need to go - then I'll do it," he said about a return to the Eels.

The former San Francisco 49ers running back admits he wasn't physically up to the challenge of playing in the London tournament last month and faces a hard slog to earn a spot in coach Ben Ryan's final 13.

"Before London, I just wanted to get over there and get a feel for the game," Hayne told Fairfax Media.

"To be able to get some game time – it was incredible. It was something I didn't think I was going to get. It was awesome to get out there and get the mental reps more than anything.

"Physically, I definitely wasn't in sevens shape. We all knew that and Ben knew that. I wasn't concerned about doing my thing over there, it was more about getting a feel for the game."

Hayne, who is now the global ambassador for Fiji Airways, undertook a huge body transformation to adjust to the rigours of NFL last year and will now begin the gruelling process to adjust to the endurance-based sevens game.

He has reservations about making the necessary adjustments in the six weeks prior to the Olympics, but insists a failure to make the squad wouldn't leave him with regrets.

"I'm not sure you know," Hayne said when asked if he would be in "sevens shape" by the time Rio rolled around.

"Hopefully, but whatever happens, happens. The biggest thing why I wanted to be over here was to be a part of the squad and a part of the build-up to it. For me, that's huge. It's always about the journey not the destination. I know I'll bring a lot being able to communicate and speaking to the guys with my experience.

"For me it's a win-win. Whether I make it or don't, at least I can pass on the experience and get the boys either ready for Rio or be a part of it myself. There's a big six weeks ahead. I'm not guaranteed tomorrow but I'll do my best today. You have to enjoy the journey in your life more than the destination. The success is in the sacrifice.

"Anyone who has followed my journey knows I love an adventure. I love using the time I've got on Earth doing whatever I can wherever I can do it. My talents have taken me across the world. I've travelled and played in another country and another continent. Now I'm in Fiji."

Hayne said he has been inundated with support from the locals since touching down in his father's native land.

"It's been great. Walking through the streets and seeing the locals, they've been great," Hayne said.

"It's great to be back here and see everyone. It is pretty hard to get a coffee or anything like that so you tend to relax around the hotel most days. There's definitely a lot of excitement around. Especially when the young kids want photos, that's when it hits home that they've obviously been watching my journey which began back in 2008 with the Rugby League World Cup."