Veteran midfielder Smith, who captained the Gills before leaving in the summer after refusing a pay cut, says he would be interested in the role if caretaker boss Ronnie Jepson is given the job full-time.
Jepson is in charge of the first-team after former manager Neale Cooper quit last week.
Smith told BBC Radio Kent: "Ronnie has probably got someone in the frame already but we'll have to see.
"The chairman seemed quite positive with regards to Ronnie.
"I'd love the assistant's job, but it depends how much work it'd involve. I want to concentrate on playing."