TPPA protestor Lizzie Sullivan says democracy is worth getting arrested for and is calling for transparency.

Police locked down one lane of Lambton Quay and made mass arrests as anti-TPPA protesters clashed with officers.

A group of about 50 protesters, calling themselves "Show us Ya Text", spent Tuesday trying to force their way into the Ministry of Foreign Affairs and Trade building on the corner of Lambton Quay and Panama St in a bid to seize documents relating to the Trans-Pacific Partnership Agreement.

At the scene, Inspector Terry Van Dillen said the arrested protesters, who blocked off the harbourside lane of Lambton Quay with a sit-in, would probably be charged with trespass. "They had an opportunity to get up and walk away."

1 of 6 Cameron Burnell/Fairfax NZ Protesters trying to seize TPPA documents are shoved back by a line of police officers at the entrance to the Ministry of Foreign Affairs and Trade building. 2 of 6 Cameron Burnell/Fairfax NZ A protester pushes against officers, head first, in a bid to breach the 16-strong cordon. 3 of 6 Cameron Burnell/Fairfax NZ A sit-in protester is warned, then arrested on Lambton Quay. 4 of 6 Cameron Burnell/Fairfax NZ A protester is dragged by police officers to be loaded into a waiting paddy wagon. 5 of 6 Cameron Burnell/Fairfax NZ A protester puts his shoulder to work against the police cordon. 6 of 6 Cameron Burnell/Fairfax NZ As police launch arrests, a protester makes things a little less easy for police.

A total of 26 protesters were cuffed, arrested and ferried in a pair of police vans, running on rotation, to Wellington central police station.

Van Dillen said at least three van-loads of protesters had already been transported. "If they go into that process and choose to get arrested, then clearly their liberty is taken out of their hands. They come into our custody."

He predicted they would probably be released later with a warning. "But it has taken up a lot of resources and a lot of time."

JOEL MAXWELL/ FAIRFAX NZ Protesters confront a police cordon outside the Ministry of Foreign Affairs and Trade headquarters on the corner of Lambton Quay and Panama St.

Senior Sergeant Bud Butler confirmed on Tuesday evening that none of the 26 arrested would be charged. All were given warnings and released, with the last protester leaving the station about 6.25pm.

Van Dillen said up to 30 police were at the scene during the day, with more staff at the station processing protesters.

Speaking from the road shortly before her own arrest, protest spokeswoman Lizzie Sullivan said they had taken to the street because they could not get into the building.

JOEL MAXWELL/ FAIRFAX NZ Anti-TPPA protesters calling themselves "Show us Ya Text" stage a sit-in on one lane of Lambton Quay, outside MFAT headquarters in Wellington. The protesters aim to enter the building and seize the text to the TPPA.

About 16 police officers formed a chain around the ministry entrance about 10.30am to stop the group from standing at the already-locked front doors.

The officers, shoulder to shoulder, advanced and pushed back the protesters to a line where the Lambton Quay cobblestones met the MFAT entrance slate tiles.

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At that point the protesters staged a brief sit-in on Lambton Quay, blocking off the lane for about 15 minutes before threats of arrest saw them move back to the footpath.

For about three hours the protesters then took turns to confront police in pairs, eyeballing officers and trying to push their way through.

Sullivan said the event was a "citizens'-initiated search and seizure" of the TPPA documents in the building.

"We think New Zealanders have a right to see what's being negotiated in our name. All this secrecy is totally incompatible with a functioning democracy."

The country had a right to see the text of the treaty and have a say on the issue, she said.

Anti-TPPA activist group It's Our Future NZ watched the protest, and its national spokesperson Edward Miller said the attempt to seize the documents was "necessary".

"The search and seizure of the Ministry of Foreign Affairs and Trade office in Wellington, taken by ordinary Kiwis to get access to the text, is an attempt to counterbalance this obsessive secrecy with people power," he said.

He said leaked documents from the TPPA negotiations indicated the agreement would transfer decision-making power from New Zealand to "foreign investors and multinational corporations".

He said Kiwis did not want New Zealand to be a part of the trade agreement. "A month ago, over 25,000 people marched in over 20 towns and cities across New Zealand demanding their government walk away from these negotiations."

A Ministry of Foreign Affairs and Trade spokesman said it had no comment to make on the protest.