Green Party ministers will release their ministerial diaries to show who they've met and why.
Ministers, MPs and staff won't accept corporate hospitality such as free tickets to events unrelated to work.
James Shaw says big corporations shouldn't have better access to politicians than those who can't afford to give out perks.
"The Green Party has always stood for more transparency around lobbying and access to politicians," Mr Shaw said.
"There's no reason why big, wealthy corporates should have better or more access to politicians than those organisations who can't afford to shout free tickets to the rugby or a corporate box at the tennis."
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Mr Shaw said MPs often consider taking corporate handouts "a perk of the job" but it wasn't essential to the role.
"It also gives wealthy corporates an advantage when it comes to influencing our country's decision-makers.
"We think New Zealanders deserve to know who's meeting with our MPs and ministers, and what the purpose of those meetings are."
NZN / Newshub.