The protesters will march from Victoria Bridge, where they have been protesting since Monday, to Briggate where they will lay on the ground and pretend to be dead.
A number of activists said they are willing to risk arrest rather than be forced to move.
The march was scheduled for noon but has now been delayed until around 4pm.
-> Live updates as the Extinction Rebellion protesters stage 'die-in' and march in Leeds City CentreAnthony Whitehouse, aged 67, has commuted to the protests from Dewsbury every day.
He said: "I don't think young people should be getting arrested, but I absolutely would.
"I'm well established, I don't have anything to protect job or career-wise.
"I quite like it! I would actually get myself slung in the nick, rather than pay a fine.
"The only way to make real change is if a small number of people put their necks on the line and are committed enough to push the system hard. That will bring on board a lot more people.
"Extinction Rebellion have a philosophy of direct action to the point of arrest, but they're very supportive of people who get arrested and they are concerned that people don't jeopardise their lives.
"It is sad to be causing so much disruption, but it is necessary."
Simon Bean, also in his 60s, said he is protesting to protect the future for his young grandchildren.
He said: "They have arrested me before and had to let me go.
"I'll do it again. I'm old, I've got nothing to lose".
Speaking about the traffic disruption, Simon added: "Last year, Leeds Bridge was closed for an entire year because of the weight of lorries crossing it.
"We're doing it for a week, and there is a route round us.
"If none of us did it, the message wouldn't get across. The more of us there are, the more we are a community and we infiltrate the wider community."
West Yorkshire Police are monitoring the protests and officers have cancelled their rest days to police the protests.
There have been no arrests so far.
A police spokesperson said: "West Yorkshire Police has deployed a proportionate number of officers to manage the protest based on assessment of potential disruption it could cause.
"Resources have been kept under review as the week has progressed.
"We have continued to work with partners to effectively manage people’s right to lawful protest, balanced with the rights and freedoms of others, and to minimise the impact on the local communities, businesses and the general public."