Macquarie Media breakfast host Alan Jones' 2GB morning radio show has lost about half its advertising revenue after a boycott over the radio veteran's comments about New Zealand Prime Minister Jacinda Ardern.

Mr Jones has faced a commercial backlash since he made comments in August that Ms Ardern should be given "backhanders" and have a sock shoved down her throat.

Despite Mr Jones apologising on air, brands have continued to abandon his top-rating show that typically brings in about $12 million a year and is worth under 10 per cent of the network's revenue.

Radio presenter Alan Jones. Many advertisers have not returned to his top-rating show. Credit:Nick Moir

Sources with knowledge of the commercial dealings at the radio business said that on an annualised basis the backlash could cost the show about $6 million in advertising, though some of the advertisers had switched to other shows at the network helping limit the hit to Macquarie's revenues overall. In September the damage was estimated to be about $1 million.