I guess you know that in c=εd/A; ε=dielectric const. is in direct proportion with capacitace 'c'. The question is incomplete. If you could tell us what was the initial dielectric then we can say 'increase; or 'decrease' w.r.t that..!!
it will increase if the dielectric coefficient increase and vice versa and it will decrease if the width of the dielectric increases and vice versa....