Sydney Airport is refusing to display a billboard that denounces tax evasion by multinational companies.
The airport, which was last year forced to pay a $69 million settlement to the Australian Tax Office to end an audit of suspect tax deductions, claimed the proposed Labor billboard would contravene its policy on political advertising.
But the Labor Party, which tried to hoist the "pay their fair share" message on General Holmes Drive, was given a different explanation from APN Outdoor, owner of the billboard.
The party was told that Sydney Airport's objection was not political but that it would cast multinationals in a negative light for business travellers arriving at Kingsford-Smith.
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.
Executives of Google, Apple and Microsoft conceded during public hearings of the Senate inquiry into corporate tax dodgers last week that they paid hardly any company tax in Australia despite earning billions of dollars in sales.
A spokeswoman for Sydney Airport insisted that the proposed message conflicted with an airport policy on political advertising.
The airport allows political messages to be displayed during election campaigns but, she said, the "concessionaire must not display any advertisement containing obscene or offensive material or any material with political, religious or racial overtones" outside campaign periods.
Mr Shorten said: "We need to be talking about this important issue, not censoring debate.
"It is not fair that Australians work hard and pay tax while big multinationals get to play by different rules. It is not fair that Australian businesses are paying more tax in Australia than big multinationals."
Sydney Airport Corporation has maintained in recent years that it complies with all its tax obligations, but a Fairfax Media investigation found in 2013 that the airport, which took on high levels of debt after being sold to Macquarie Bank in 2002, paid no company tax in the decade between 2003 and 2013.
The company has argued that its "flow-through" structure, similar to a stapled property trust, passes the tax obligation on to investors.
Last year it was revealed that Sydney Airport had paid $69 million to the ATO to end an audit that raised questions over deductions claimed on billions of dollars' worth of redeemable preference shares used to finance the business.
