* Harper meets about 20 chiefs; some native leaders boycott
* Ontario chief threatens blockades on Jan 16
* Nova Scotia rail line blockaded
* Idle No More aboriginal movement picks up steam
OTTAWA, Jan 11 (Reuters) - Aboriginal protesters blocked the main entrance to a building where Canada's prime minister was preparing to meet some native leaders on Friday, highlighting a deep divide within the country's First Nations on how to push Ottawa to heed their demands.
The noisy blockade, which lasted about an hour, ended just before Prime Minister Stephen Harper and his aides met with about 20 native chiefs, even as other leaders opted to boycott the session.
Chiefs have warned that the Idle No More aboriginal protest movement is prepared to bring the economy to its knees unless Ottawa addresses the poor living conditions and high jobless rates facing many of Canada's 1.2 million natives.
Native groups complain that successive Canadian governments have ignored treaties aboriginals signed with British settlers and explorers hundreds of years ago, treaties they say granted them significant rights over their territory.
The meeting was hastily arranged under pressure from an Ontario chief who says she has been subsiding only on liquids for a month. It took place in the Langevin Block, a building near Parliament in central Ottawa where the prime minister and his staff work.
Outside in the freezing rain, demonstrators in traditional feathered headgear shouted, waved burning tapers, banged drums and brandished banners with slogans such as "Treaty rights not greedy whites" and "The natives are restless."
Until midday on Friday, it was uncertain if the meeting would go ahead, with many native leaders urging a boycott and others saying it was important to talk to the government.
"Harper, if you want our lands, our native land, meaning everyone of us, over my dead body, Harper, you're going to do this," said Raymond Robinson, a Cree from Manitoba.
"You'll have to come through me first. You'll have to bury me first before you get them," he shouted toward the prime minister's office from the steps outside Parliament.
The aboriginal movement is deeply split over tactics and not all the chiefs invited to the meeting turned up. Some leaders wanted Governor-General David Johnston, the official representative of Queen Elizabeth, Canada's head of state, to participate.
Johnston has declined the invitation, saying it is not his place to get involved in policy discussions. He instead was later hosting a ceremonial meeting with native leaders at his residence. The elected leader of the natives, Assembly of First Nations National Chief Shawn Atleo, was one of those who attended the meeting with Harper.
He said his people wanted a fundamental transformation in their relationship with the federal government, and would press for a fair share of revenues from resource development as well as action on schools and drinking water.
BANGED ON THE DOOR
Gordon Peters, grand chief of the association of Iroquois and Allied Nations in Ontario, threatened to "block all the corridors of this province" next Wednesday unless natives' demands were met. Ontario is Canada's most populous province and has rich natural resources.
Peters told reporters that investors in Canada should know their money was not safe.
"Canada cannot give certainty to their investors any longer. That certainty for investors can only come from us," he said.
Manitoba Grand Chief Derek Nepinak, who said on Thursday that aboriginal activists have the power to bring the Canadian economy to its knees, was one of the leaders of the protest at the Langevin Block.
"We're asking him to come out here and explain why he won't speak to the people," said Nepinak, who banged on the door at the main entrance to Harper's offices after choosing to boycott the meeting.
Nepinak and other Manitoba chiefs are also demanding that Ottawa rescind parts of recent budget acts that they say reduce environmental protection for lakes and rivers. The most recent budget act also makes it easier to lease lands on the reserves where many natives live, a change some natives had requested to spur development but which others regard with suspicion.
Ottawa spends around C$11 billion ($11.1 billion) a year on its aboriginal population, but living conditions for many are poor, and some reserves have high rates of poverty, addiction, joblessness and suicide.
Harper agreed to the meeting with chiefs after pressure from Ontario chief Theresa Spence, who has been surviving on water and fish broth for the last month as part of a campaign to draw attention to the community's problems. Spence, citing Johnston's absence, said she would not attend.
"We shared the land all these years and we never got anything from it. All the benefits are going to Canadian citizens, except for us," Spence told reporters. "This government has been abusing us, raping the land."
In Nova Scotia, a group of about 10 protesters blockaded a Canadian National Railway Co line near the town of Truro on Friday afternoon, CN spokesman Jim Feeny said.
A truck had been partially moved onto the tracks and was cutting off the movement of container traffic on CN's main line between the Port of Halifax and Eastern Canada, he said. Passenger services by Via Rail had also been disrupted.
The incident was the latest in a series of rail blockades staged by protestors in recent weeks to press the demands.