More than 400 people protested outside the Royal Court
Hundreds of anti-incinerator protesters lobbied deputies going into the Guernsey States Chamber on Wednesday.
More than 400 people, some with banners, gathered on the steps of the Royal Court building in St Peter Port.
They asked deputies not to reinstate the proposals for a waste-to-energy mass-burn incinerator, which were scrapped last month.
Some deputies were heckled while others voiced their support for the protesters.
Deputy Minister of the Public Services Department Scott Ogier, who has been charged with bringing a new waste strategy forward, said it showed the strength of public feeling on the issue.
He said: "I've never seen anything like this at all, it's absolutely amazing. The people of Guernsey have sprung up and have come here to tell the deputies how they feel.
"It's such a great and healthy democracy that we have here and I'm delighted to be a part of it."
Rupert Dorey, one of the organisers of the protest, said: "It's the most fantastic, powerful statement of people power and I sincerely hope all the politicians will take notice of what people are saying here.
"I'm delighted it has been peaceful and good-natured, it really is Guernsey speaking."
Before the States meeting in February which saw the plans for an incinerator binned, there was a similar anti-incinerator protest by 80 people.
Deputies were invited to two sessions earlier in the week, which presented the plans for a waste-to-energy incinerator proposed by Suez Environment, the company who before last month's decision had been the States' preferred partner.