Peter Cundall, the former host of the ABC's Gardening Australia program, has used the publicity surrounding his court appearance to accuse logging company Gunns and the Tasmanian Parliament of corruption.

The 82-year-old gardening celebrity was arrested during a protest against Gunns' pulp mill outside State Parliament last year.

This morning he pleaded not guilty to the charge of refusing to obey a police order to move away from Parliament House and now hopes to fight the charges in a test case.

Outside court Cundall was having another swipe at Gunns and the politicians who approved plans to build Australia's biggest pulp mill in the Tamar Valley.

"When you get a situation where a major proponent of a major pulp mill can actually donate to the main political parties and then cooperate in preparing that legislation for Parliament and passing that through, that is corrupt and I'm fighting against that," he said.

Cundall is one of 57 anti-pulp mill protesters who were arrested out the front of Parliament House in November last year. Several have pleaded guilty, but not Cundall.

He and at least 12 others pleaded not guilty this morning. Their lawyer Roland Brown is negotiating with the police prosecutor to run one case as a test to determine the lot.

"There's a lot of allegations about corruption in the pulp mill process. There's a lot of allegations about the relationship of the timber industry and the Government and Forestry Tasmania, and I can tell you that that is not part of this case," he said.

"This case is going to be relating to the lawfulness of people being at Parliament House to protest, to talk about corruption like that."

Cundall says he will be the test case and is using it to push his line that Gunns is corrupt. He says the anti-pulp mill protest was peaceful and legal.

"We did not block any doorway. We had done absolutely nothing wrong," he said.

"We even placed little markers on either side of the doorway to make sure it was not blocked. We were not intending to commit any offence at all."

'No denial''

Now that Cundall has retired from presenting Gardening Australia, he is using his celebrity status to fight the pulp mill.

"It was corrupted because the proponent of the mill was allowed to help prepare the legislation to pass its own, to pass the legislation through Parliament," he said.

"They were actually helped there with the parliamentary draughtsman and worked with him to prepare ... and as a result the legislation went through.

"Give the people anywhere absolutely no recourse to the law if anything should go wrong."

Cundall says the proof that Gunns helped write the legislation is that they have not denied it.

"It's been pointed out several times, in fact, they helped prepare and they simply haven't denied it," he said.

"And just the same as many of the members of Parliament have not denied that their families have a certain peculiar interest, that's another thing too.

"So here's another - I keep saying and using the word corruption. I use it deliberately. Why has nobody sued me?

"And the reason why is because if I go into court accused of calling somebody corrupt, I'll be there with evidence to say this is what happened. They don't want that."

Gunns is not commenting on Cundall's claim that the company used corrupt means to get its pulp mill approved.

But under the law, Gunns is not able to take legal action against Cundall because corporations with more than 10 employees cannot sue for defamation."