Deputy Premier Troy Grant is preparing to hand the pubs and clubs that operate pokies in NSW a potential $40 million windfall under proposed changes to fees associated with monitoring the machines.

Mr Grant has pledged to change the indexation of a monthly fee paid by most pubs and clubs operating poker machines to the private operators of the Centralised Monitoring System (CMS).

Deputy Premier Troy Grant said removing IPART's role in setting the pokies monitoring fee "provides certainty of cash flows to the new licensee". Credit:Josh Robenstone

Under NSW law poker machine owners - with some exemptions - must pay the fee to the CMS operator, which monitors the integrity of the poker machines and ensures the correct amount of tax is paid to the state government.

Since its inception in 2001 the monthly fee - currently about $42 plus GST per poker machine per month - has risen by a flat 3 per cent per year as determined by the Gaming Machines Act.