In a note, Gardiner said forecasting the fire's impact on SkyCity was a "moving target" with potential changes likely as more information became available on construction timing, insurance cover, costs to SkyCity and indirect impacts such as hotel occupancy.
"It is still early days with the finer details around insurance still to be disclosed," he wrote. "Management appears confident that insurance arrangements are in place for the reconstruction of the development, but at this point we are unsure as to the revised time-frame for the development to be completed, and the extent to which insurance will cover business interruption."
Gardiner has reduced his expected earnings before interest, tax, depreciation and amortisation (ebitda) for SkyCity by between 2 per cent and 7 per cent for its financial years ending 2021, 2022 and 2023.
But he estimates only a slight impact in SkyCity's current financial year, with ebitda down from $303.6m to $301.1m.
Gardiner also assumes that an increase in casino visits stemming from the new International Convention Centre would now be delayed until the 2023 financial year and there would be reduced occupancy across its entire hotel portfolio until the new convention centre opened.
Despite the uncertainty around the business, Gardiner has retained his "buy" rating on the stock with an assumption that insurance proceeds would fully cover the reconstruction of the convention centre.
But he said there may be few positive catalysts for SkyCity's share price while uncertainty around the insurance and timing remains.
Gardiner believes the dividends will not be affected by the fire.
SkyCity chief executive Graeme Stephens has said it will be weeks before the convention centre is secure enough to properly assess the damage, and at least a month or two before it is clear exactly how much damage there is.
SkyCity's shares closed at $3.98 on Monday, the day before the fire and last traded at $3.91.