A chief, who once went to jail for defending his First Nation's traditional territory during a mining dispute in northern Ontario, says he has grave concerns about Bill C-51.

Kitchenuhmaykoosib Inninuwug Chief Donny Morris sent a letter to his MP, Natural Resources Greg Rickford, asking him to withdraw support for the proposed anti-terrorism law.

Morris and six others from Kitchenuhmaykoosib went to jail in 2008 after peacefully protesting mining activity near Big Trout Lake, about 600 kilometres north of Thunder Bay, Ont. He's worried that under Bill C-51 the consequences for Indigenous activists will be much worse.

"I take this to my heart," Morris said. "Because I know it will happen. It happened to us. We got sentenced. We got sent to jail, what's going to stop an officer from taking that next step."

That next step, in Morris' mind, is First Nations people being shot by police during land-based disputes.

"That's what I don't want to see in the future to our native brothers and sisters," he said. "That they lose their life over something that is sacred to us."

'I'm still being watched'

The dispute at Kitchenuhmaykoosib was resolved in 2009 when Ontario bought out the claims of the mining company involved. The First Nation later developed its own watershed declaration and protocols to protect its traditional territory from unwanted development.

Still, Morris worries about how his activism is perceived by government.

"I'm still being watched or monitored and viewed as a... terrorist," he said. "That's the sad part and the part that hurts me the most."

Rickford has a large number of First Nations in his riding and should consider the implications of the anti-terror law on them, Morris said, adding he hasn't had a response to the letter.

A spokesperson for Rickford told CBC News that the Minister received the letter from Morris on Tuesday and "will respond in due course."

"The legislation is clear: our security agencies can only target those who pose a risk to Canada, and not those engaged in legitimate dissent," Alexandra Lemieux said in an email.

The House of Commons public safety committee is holding hearings on Bill C-51 this week.