About 8000 people marched on central Auckland on Saturday afternoon as opposition grows to the Government's mooted asset sales.

A march supporting the 'Aotearoa is not for Sale' hikoi descended on the city shortly after 3pm, heading up Queen St to Aotea Square for a rally.

The hikoi - which was launched in the Far North on Tuesday - is travelling the length of the North Island to protest against a raft of issues, including the Government's planned asset sales.

NEIL REID/Fairfax NZ NO HOLDS BARRED: Protestors chanted "John Key, you suck eggs".

Veteran protestor John Minto was among the gathering, telling the crowd that "there was no way Aotearoa is up for sale".

He said the country was "under attack", but added 2012 was the year for everyday New Zealanders to "fight back".

Earlier, protestors had chanted "John Key, you suck eggs" and "Aotearoa is under attack".

It will take two weeks to reach Wellington, before kick-starting a week of hui and protest action around the capital city.

A statement from hikoi organisers said: "The hikoi will express public opposition to privatisation and the selling off of our country's assets, natural resources, land and public services.

"Most New Zealanders don't want our public assets, resources and farm land sold to private investors. It is not in our interests to put our future in the hands of a few large foreign companies whose primary goal and self-interest in profit undermines what is good for the country we live in and love.

"If we don't act now, looking back in 15 years' time, our country could have overseas corporations buying and bullying political favours and oucomes. This is the message the hikoi will take to Wellington ... this is not the brighter future many of us dream of."

While the hikoi is not aligned to anyone political party, today's protest activities in central Auckland figured officials from Labour, Mana, the Maori Pary and the Greens.

Meanwhile, earlier today about 500 people marched through Nelson in another protest action against the mooted asset sales.

Chanting slogans, the marchers walked up Trafalgar St to the Church Steps, where they heard speakers from the Green, Labour, and New Zealand First parties as well as Greenpeace and the Campaign Against Foreign Control of Aotearoa.

The common theme was that the Government didn't have a mandate to sell shares in state assets and that the decision could be overturned if the campaign was maintained.

A message from Nelson's National MP Nick Smith, who was in Dunedin, was drowned out by boos and a "not for sale" chant and former soldier Gareth Palmer was cheered when he said that in his eyes: "John Key is a traitor".