Although the Millers have yet to nail down a site for the proposed 15,000 capacity ground, Stewart insists there is no need to push the panic button.
"I'm fully aware of the concerns of supporters and that they are anxious for news," Stewart told the Advertiser.
"What I can tell them is that we are still in keeping with our time chart and we have a little bit to spare.
"The planning process was always going to take a long time. I'm aware that we have to perform to get to where we need to be for the start of the 2012/13 season but I'm doing my level best not just to meet that date but to beat it.
"If we have not started building work in 18 months' time, it's then I will be worried."