Labor has seized on a NSW Treasury document that says the sale of the state's remaining stake in WestConnex is a "live option", as evidence of the government's plans to privatise more state assets.

But Treasurer Dominic Perrottet has accused the Opposition of scaremongering, insisting that the government has "no plans" to sell the remaining 49 per cent interest in the $16.8 billion toll road.

The trading of blows as both sides enter election campaign mode came after a NSW Treasury response to a freedom-of-information application from Labor stated that "a further sale of the government's equity [in WestConnex] remains a live option under deliberation".

NSW Labor leader Michael Daley said the documents showed that the government wanted to sell more state assets despite people having had enough of privatisations.