Not all lobbyists lie and mislead and some are crucial to democracy, a corruption watchdog commissioner says.
A parliamentary inquiry examining the levels of lobbyist access to Parliament House has heard calls for enforceable standards, with harsher penalties for those who break them.
Though lobbyists have been associated with corruption risks, NSW Independent Commission Against Corruption (ICAC) chief commissioner John Hatzistergos says some provide vital feedback to political systems.
"Lobbying, when done well, can enhance rather than detract from good decision-making by public officials," Mr Hatzistergos told the parliamentary committee on Monday.
"In this way, lobbying is essential to the success of representative government."
Transparency is integral as secrecy is what leads to distrust, the commissioner said.
"That's not to say, that lobbyists may not lie intentionally, mislead political decision-makers or present misinformation to their own ends," he said.
"(But) promoting the transparency of lobbyists' actions can shed light on the black box of policymaking, and also serve to make political officials more accountable."
Managing director of lobbying firm Hawker Britton, Simon Banks, said a code of conduct legislated by parliament was needed to ensure standards were kept.
Enshrining the code would bring the Commonwealth up to date with Canada, the UK and most of the nation's states.
While the Attorney-General's Department administers a code of conduct for lobbyists, it does not extend to those who have access to parliament house.
There are almost 1800 lobbyists who have been issued security passes after being sponsored by an MP and who are then allowed to roam the corridors unaccompanied.
Mr Banks said the code should be extended to those with parliament house security passes.
The inquiry also heard calls to increase transparency about the details of lobbyists with access to parliament house.
While Hawker Britton supported calls for the names of lobbyists to be publicly available, Mr Banks said there would still be some exceptions.
Some details may need to be kept private should they be politicised or used for trolling, he said.
"Otherwise, I think the general rule that should apply is that the system should be as transparent as possible."
Vivien Clark, from the Australia Institute, told the inquiry that access to parliament house should not be limited, to better ensure accessibility to politicians.
"The most powerful commercial interests don't need access to parliament house, to access ministers and parliamentarians," she said.
"It's civil society, academics, trade unions, community groups and other members of the public who depend on access to parliament house in order to access decision-makers."
The hearing was told by officials from the Attorney-General's Department that they had not been instructed by government to look at having a legislated code.
Independent senator David Pocock said Australia might be in breach of the World Health Organisation's Framework Convention on Tobacco Control, which meant big tobacco did not have access to legislators or people regulating the industry.
This was due to the likelihood of employees of big tobacco companies having access to sponsored passes.
"This is the one thing where we have some sort of obligation around lobbying internationally and yet we're not even tracking it," he said.
"To me, it kind of exposes just how loose this whole system is."
Australian Associated Press
