"But for the most part I wouldn't say there's a problem. Over 2000 vehicles successfully going through the bollards shows that it's successfully working."
The bollards retreat into the ground when activated by a sensor inside a vehicle.
Milne said timing was crucial, because there was only a small window to drive over them.
"You get a certain amount of time to go across, and it's not an unrealistic time to be able to do that. But we will have a look at that.
"It wouldn't be a particularly good safety barrier if they went back down on touching a vehicle. The whole point of them is to stop [cars]."
The bollards were out of action today. But they will be re-started again tomorrow, possibly after a few adjustments.
The additional safety measure was introduced after a security threat on Budget Day in which a man drove a ute onto Parliament's forecourt.