NSW Labor's left faction is pushing for a broad-based land tax to be considered at its annual conference as an alternative to calls by Premier Mike Baird and others for GST increase.

Left faction delegates to next weekend's state conference have agreed to push for a resolution to be placed on the agenda, with the specific wording to be thrashed out inside the party this week.

Prime Minister Malcolm Turnbull with media adviser John Garnaut. Credit:Andrew Meares

An article in the left's Challenge magazine, due to be published next Saturday, argues a broad-based land tax is "a natural replacement for the hated stamp duty on conveyancing".

The article says land tax is "inherently progressive", as opposed to taxes like the GST which "disproportionately punish low- and middle-income earners".