Walker said he was confident the company was acting within the law, because the company did not give "free" products.
"We've sought legal advice on this matter," he said. "Individuals choose to test our product. They give us feedback on that. It's entirely up to an individual whether they see it as a perk or not."
Walker also confirmed there were no health warnings on the containers which staff take cigarettes from. He would not be drawn on whether the company kept tabs on the number of staff involved or how many cigarettes were given.
"I certainly wouldn't describe them as guinea pigs ... It's important we test our products, we want to ensure we offer a quality product to our smokers."
Hutt Valley Regional Public Health smokefree officer Kristen Foley said he would seek discussions with the company bosses next week and it was too early to determine whether the multi-national company was breaking the law.
Imperial Tobacco has a growing market share in New Zealand, with 16 cigarette and loose tobacco brands.
It recently embarked on a $50 million development project and announced plans to employ 50 extra staff on top of its existing 200.
Action on Smoking and Health director Ben Youdan said he would be disappointed if the company was able to get around the legislation.
"It's appalling. Why go to the effort of having health and safety, steel capped boots, all of that, if you're going to provide a product during the tea break that will eventually kill half of them?"
Recently retired Petone GP Dr Ian Milne said he treated Imperial employees and most of them smoked.
Factory smell complaints
Imperial Tobacco was also under fire this week over emissions from chimneys at its Petone factory.
The factory has just moved to an around-the-clock operation and local residents had complained to the authorities over increased odours.
Imperial's commercial boss Brendan Walker said the company upgraded part of its facility. The Wellington Regional Council visited the factory on Friday and confirmed it complied with resource consent.
"The odour is a result of steam created during our tobacco blending process," Walker said.
On whether the emission was harmful to the public, he said: "I'm not a chemist, I don't know. I would almost certainly say no. It really is just steam and tobacco leaf. It really is just steam."