NSW Premier Gladys Berejikilan's government will be returned to power after the Labor opposition was only able to secure a modest swing in an election campaign fought over how to spend the state's huge tax revenues.

With half the votes counted, the Coalition had secured about 45 seats in the 93-seat parliament. Early counting estimated there was a swing to the Labor Party of 1.5 per cent, far short of the 3.2 per cent uniform shift needed to take out the government's parliamentary majority.