The price of petrol has dropped for the second time in almost as many days.

Saturday saw a four cent drop, with another four cent drop occurring today.

Shell and BP led the charge, with 91 Octane now just under $1.55 a litre, and 95 Octane just under $1.62 a litre.

Diesel remains unchanged at just under $1.00 a litre.

However, these latest drops will be largely offset by a fuel excise duty increase of 3 cents per litre, which is due to come into effect on Thursday.