People might be dodging the tax man, without even knowing it

Data shows there's 80-million dollars missing - which has led to tax investigators are door knocking speculators, in a quest to recover the unpaid property taxes.

It includes those trying to dodge the bright-line law by not paying tax when a property's flipped within five years.

But OliverShaw Tax Advisors director Mike Shaw says a lot of people are caught by the law - without even knowing it.

He says they've come across many situations where a family have bought a second home with the intention of moving into it, but then their situation changes.