Correspondence obtained by Fairfax Media shows an APN Outdoor employee clearly stated that the issue hinged on a perceived smear on multinationals.

"The issue was less that it was political but that the creative addresses foreign multinationals in a negative light, and because it is placed near the airport it's not the ideal location for that sort of message," APN Outdoor said in an email sent to an intermediary that had booked the billboard.

But APN Outdoor chief executive Richard Herring said on Wednesday that the issue was Sydney Airport's policy on political advertising.

After being shown the email, he said that a "junior employee" had presented their own interpretation but that explanation did "not represent the position of APN Outdoor or Sydney Airport".

The ALP, which had used the same billboard on General Holmes Drive during the NSW state election campaign, had planned to reuse it as part of a snap campaign to capitalise on public anger at corporate tax evasion launched on Saturday.