Taxi passengers crossing the Sydney Harbour Bridge and Harbour Tunnel northbound will no longer have to pay the cost of a return toll of up to $4 after new laws covering the taxi and ride-sharing industries come into effect on Wednesday.

Under the changes, taxi-booking companies such as Cabcharge will be also able to set their own prices and potentially offer "frequent rider" discounts and match prices of ride-sharing companies such as Uber.

People booking taxis and hire vehicles will be able to ask for an estimate of the price of a trip before they get into a cab, which could be a fixed amount or a rate per hour or kilometre. Customers will have to accept the estimate before the trip begins.

NSW Point to Point Transport Commissioner Barbara Wise said taxi companies would now be able to set their own fares for trips booked by phone or app, allowing them to set a flat fare for trips such as from Sydney Airport to the CBD.