Tobacco companies are trying to pry confidential documents from government departments as they battle a possible crackdown on their trade.

An anti-tobacco group has expressed concerns that the companies are trying to "bog down" civil servants, while Associate Health Minister Tariana Turia says the Government will not be slowed down by any tactics.

Information obtained by the Sunday Star-Times revealed legal representatives for several tobacco companies filed at least nine Official Information Act (OIA) requests to the Ministry of Health in the past two years for documentation relating to plans to ban brand marks and logos on cigarette packets.

The companies' requests covered a wide array of information, including documents relating to:

All communication about plain packaging between the Ministry of Health and its Australian, Canadian and British equivalents;

how plain packaging would affect youth and adult smoking rates in New Zealand;

how plain packaging would impact on the intellectual property rights of tobacco manufacturers;

and whether plain packaging would violate any of New Zealand's trade and investment treaty obligations.

British American Tobacco was the most prolific company, with its legal representatives filing six OIA requests during the period.

The company's first request, sent in May 2011, consisted of 63 separate points for documentation on plain packaging reform.

Philip Morris also sent two requests, while Imperial Tobacco filed one during the two-year period.

The requests were largely declined, with Turia citing the "substantial collation or research" required to gather much of the information and the confidentiality of some documents.

However, several Cabinet papers related to plain packaging reform were released, while the companies were told that other information it had requested would soon be publicly available.

The director of anti-tobacco group Action on Smoking and Health (Ash), Ben Youdan, believed the companies were trying to "hold up and bog down" civil servants who had to process the requests.

Youdan worked for the Australian government while it was passing its own plain packaging laws, and said tobacco companies had filed 53 official information requests to the country's health department in 2011 - costing about $600,000 to process.

"A lot of it is about wasting time, and holding up the political process by tying up the time of civil servants who should be informing public policy."

Youdan said tobacco companies' "unprecedented" response to the threat of plain packaging showed they were concerned about smoking rates going down.

British American Tobacco New Zealand corporate and regulatory affairs head Susan Jones said the company had filed its requests to find out more about the Government's plans and how they could affect its business.

"Tobacco is a legal product, [British American Tobacco] is a legal business and - like any business - we have a right to make reasonable requests about information that could affect us." The company "strongly refuted" any allegation that it was misusing the OIA process, Jones said.

Philip Morris and Imperial Tobacco also cited concerns about government policy affecting their business as reasons to submit OIAs.

Turia said the requests would not slow the ministry down as it continued to develop plans for plain packaging.

"They may think that by flooding the ministry with all of these OIAs, they will take the ministry away from the work it is doing, but it doesn't matter how many requests they make - we are on track."

Turia said Cabinet was still considering a paper about plain packaging, but was confident the reforms would go ahead.

"The support we've had right throughout the country on this issue has been really significant; not just the anti-tobacco advocacy groups, but also taxpayers have been very clear in the feedback they've provided to us," she said.

- © Fairfax NZ News