The NSW coalition will have to borrow an extra $7.3 billion to fund its election promises, according to an independent analysis of the party's costings.
The parliamentary budget office on Monday released its budget impact statements for both the coalition and Labor.
The PBO found the government's net borrowing would increase from $38.6 billion to almost $46 billion over the forward estimates.
The budget would be $700 million worse off under the coalition over the forward estimates compared to the current projection while it would increase under Labor by $1.4 billion.
However, Labor's plan to abolish the 2.5 per cent wages cap with the intention of increasing pay for public sector workers wasn't costed by the PBO.
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NSW Treasurer Dominic Perrottet said if the wages cap crept up to 3.5 per cent it would leave a $5.1 billion hole in the state surplus over the forward estimates.
"The cost would be billions of dollars off the budget position," Mr Perrottet told AAP.
"There is no cost only because the PBO have stated they are unable to cost it and the impact on the budget is not known."
He said that black hole meant Labor's costings "weren't worth the paper they were written on".
Mr Perrottet said Labor's predicted budget surplus increases would be paid for by "massive tax hikes and cancelled projects".
Meanwhile, costing of Labor's plan to make public transport for children and students free did not factor in additional bus or train services being added to the network to service demand.
The PBO said Transport for NSW had warned there was limited existing capacity to absorb demand.
Opposition treasury spokesman Ryan Park warned the coalition would have to consider privatising more public assets to pay for the additional $7 billion in borrowings.
"The simple question that Premier Berejiklian must answer is will she privatise hospitals first or the rest of the electricity network?" he said in a statement.
Meanwhile, Labor's luxury car and boat tax - meant to raise $240 million to pay for more nurses - fell short by $13 million, according to the impact statement.
