The 28-year-old has been linked with a move to Tottenham after scoring 22 Premier League goals last season.
Asked again about the Englishman's future, Hasenhuttl said: "I've already given a very, very clear answer to this question – we will have Danny for a very long time with us and this is all I can say."
Saints managed their first win of the season on Saturday against Burnley, with Ings scoring the decisive goal in the 1-0 victory.
But Hasenhuttl wants his other strikers to start easing the load on Ings.
"We must always pay attention that we are more than only Danny Ings," he added.
"He scores for us but the guys are working for him. Che (Adams) made a fantastic assist.
"The guys are working hard, he (Ings) is working hard for the team. He's a very important player for us.
"Together, when everybody is performing well we are a good team and, in the end, it's important for him to stay fit and then he's always there to score."