Alison Gelder, from Housing Justice, says changes to welfare benefits and people losing benefits have partly caused the rise, as well as an increasing amount of people living in private sector accommodation, who are evicted once their contract runs out.
Mrs Gelder is calling on the government to build more affordable housing, and to provide a form of emergency shelter to everyone who finds themselves on the streets, regardless of whether they're an immigrant or why they left their previous accommodation.
She was speaking as figures from the Department for Communities and Local Government found 2744 in England slept on the streets on average every night in 2014.
When government started recording rough sleeping in England in 2010, the figure was 1768 people on average per night - signalling a rise of 55% since then.
The problem has particularly worsened in London, which has seen an increase in rough-sleeping of 37% since last year, compared to 7% in the rest of England.
Of the 2744 people on average sleeping on the streets every night, more than 1 in 4 of them were in London (27%).
Alison Gelder told Premier's News Hour: "We knew that the number was going to go up because what Housing Justice does is helped churches open winter night shelters, and we know that the numbers in night shelters have been high all the way through this season.
So we weren't surprised, we're just really, really saddened. It's scandalous, isn't it?
"Any market if there's more supply the price will eventually come down so that's part of it [the solution], you can do things like controlling people's rents... you can build more social housing...
"Last winter in London we know that at least 1500 people stayed in church night shelters, and that's just in London. So those people would've been on the streets if it wasn't for the shelters, so we're saving people's lives.
Homelessness Minister Kris Hopkins said: "As a result of the successful introduction of the 'No Second Night Out' initiative in London, which we are supporting other areas across England to take up, more rough sleepers are now being found and given the help they need and around three-quarters of new rough sleepers in London do not spend a second night on the streets.
"I remain concerned - particularly about the rise in foreign national rough sleepers in London.
"With over half of London's rough sleepers now being foreign nationals it is important that migrants who come to this country are able to support themselves so they do not become destitute.
"We are working with the Home Office, local authorities and charities to improve voluntary returns to the migrant's home country and, if appropriate, enforced return."
Listen to Alison Gelders speaking to Premier's Marcus Jones on the News Hour: