Your accountant is correct.
The purchase costs get added to the cost base - so only become tax deductible on the sale of the asset (if used as an IP the whole time).
Although MI and loan est. fees get ded'd over 5 years, from memory - just check.
IP now & while it is ever an IP = all costs fully tax deductible.
Tax deductability stops when you use it for private purposes = when you move in as your PPOR