Sydney radio station 2GB's star broadcaster Alan Jones has triggered an advertising boycott after he used a racial slur on air during a segment on the leadership rumblings in Canberra.

The NSW Law Society, which represents the state's 30,000 solicitors, announced on Monday it had "pulled all advertising from 2GB, effective immediately" after Jones used the phrase "n----- in the woodpile" during his breakfast radio show last Thursday.

Broadcaster Alan Jones says he regrets using an 'old and offensive figure of speech'. Credit:Bryan O'Brien

The society, which condemned the comments as "inappropriate and offensive", is one of a small number of advertisers to boycott the radio station in the wake of Jones' comments, for which he subsequently apologised. Vodafone also suspended advertising in the wake of the controversy.

"The Law Society will not align itself with platforms that allow offensive, racist or divisive commentary in our community," the society said in a statment.