The striker, who turns 36 in October, has been United's key player this season, scoring 26 goals in all competitions after signing on a free transfer from Paris Saint-Germain last summer.
United expect Ibrahimovic to stay for at least another year, although he is yet to confirm if he will take up the 12-month extension option on his current deal.
Speaking to Omnisport, Neville was asked whether he would give Ibrahimovic a two-year deal and the former United full-back responded: "I'd say yes. Because of the professionalism, the training and his commitment to the club.
"I think United needed personalities and characters after what happened in the previous few seasons. A lot of United's success has revolved around him.
"It will be impossible for him to play every single match in that period. There has to be a dip at some point. Ultimately, it's how Mourinho manages him over a two-year period because he wants to play every match.
"The reality is, I'm not quite sure that will be able to happen as he continues to get a little bit older."
Major League Soccer club Los Angeles Galaxy are said to be monitoring Ibrahimovic's situation at Old Trafford with a view to making the Swede the highest-paid player in MLS history.