The 26-year-old has been a mainstay in the Saints team over the past few years.
He has been in excellent form this term, helping the club to a position near the top of the league so far.
Ward-Prowse has more passes and touches of the ball than any Saints player this term.
Asked by reporters about how Ward-Prowse will progress into his late 20s, manager Hasenhuttl told the Daily Echo: "It is not surprising when I say that he is one of the best midfield players in the Premier League, absolutely.
"He is not only fantastic at free-kicks but he also displays a massive workload every game.
"He can run more than any other player.
"He is robust. He is gifted. He is technical. He is very, very smart.
"This is not such a bad combination, to be honest."