The state government is poised to ramp up borrowing and move within one economic shock of falling into net debt.
It will narrowly avoid net debt if the latest budget estimates prove accurate.
Treasurer Peter Gutwein said the government would remain net debt free, and that was supported by the forward estimates out to 2021-22.
However, the amount by which cash, deposits and investments exceed borrowings is forecast to slide from a healthy $622.4 million in the current financial year to as little as $14.8 million in 2020-21.
The borrowing hike relates to infrastructure spending.
Mr Gutwein said he was comfortable with the situation because the borrowing would go towards an infrastructure program which would drive investment, jobs and government revenue.
Shadow Treasurer Scott Bacon said Mr Gutwein appeared determined to drive the state into net debt.
Aside from the flirtation with net debt and lingering uncertainty about future GST distributions, the budget looks to be in rude health, with a stronger economy helping underpin a strong run of predicted surpluses.
The state government is budgeting for a $161.9 million surplus in 2018-19, followed by estimated surpluses of $113.7 million, $148.3 million and $196.4 million in the following three years.
It has also revised up its estimated surplus for the current financial year from the $54.3 million predicted in last year's budget to $75.3 million.
The budget forecasts government revenue growth of 2.1 per cent a year over the next four years, and spending growth of 1.6 per cent a year.
"We will continue to live within our means," Mr Gutwein said.
"A balanced budget delivering surpluses that provide an appropriate buffer is critical to ensuring we can deal with any unexpected events.
"In recent weeks, those opposite have raised risks associated with the GST, while at the same time calling for public sector pay rises that run ahead of inflation.
" ... you cannot have it both ways."
Prime Minister Malcolm Turnbull on Thursday said Tasmania would be "very happy" with the GST outcome.
Mr Gutwein said it was the first year ever at this stage he had had a GST projection guaranteed by a prime minister, so he felt more confident about the budget's GST projection than he ever had.
The budget predicted progress on an alternative outcome measure, the underlying net operating balance.
That strips out federal infrastructure grants and, in the view of economist Saul Eslake, gives a clearer view of the budget position.
Last year's budget predicted a run of underlying net operating deficits over the following four years.
That prompted Mr Bacon to recently chide Mr Gutwein that he had never produced a real surplus.
The current budget forecasts a slim $11.1 million underlying operating surplus in the last of the out years (2021-22).
It also included a $4.5 million deficit on that measure in 2018-19, and deficits of $82.6 million and $10.3 million in the following two financial years.