Grand Theft Auto 5 may not be confirmed for PlayStation 4 or Xbox One yet, but Rockstar believes that the game already "feels 'next generation'".

Speaking to IGN, Rockstar North associate technical director Phil Hooker said that GTA 5 "surpassed [Rockstar's] own expectations", with substantial improvements made to the gameplay and graphics from GTA 4.

"When we started we knew the scope of GTA 5 was huge and incredibly ambitious," said Hooker. "Fortunately from completing GTA 4 we had a team that was already very familiar with the hardware.

"Every aspect of the game had to be better, richer in gameplay and more fluid and knowing we were launching on the same platforms meant we could focus on extracting the most out of those consoles and making the game as fantastic as possible.

"In the end we surpassed our own expectations and during development I think everyone working on the game has been astounded by improvements to the graphics, or new mechanics, or AI, or mission scope along the way.

"Hopefully the gamers will see all of these improvements at once in one go, compared to GTA IV this definitely feels 'next generation' to us."

It still isn't clear whether GTA 5 will make it onto next-gen platforms, with producer Leslie Benzies stating that the team is focussed on getting "the current gen version out first" before seeing "what happens in the future."

GTA 5 launches on Xbox 360 and PlayStation 3 on September 17.