Cari Mitchell, from the English Collective of Prostitutes, said it would force the problem underground and failed to address the causes that led to women becoming sex workers.
"When the murders took place, there was a public outpouring of compassion and demand that things should change, and people really did grasp that it was because women were criminalised that they were so vulnerable," she told Reuters.
"Despite this, the reaction of the government, Ipswich council and police was to put out a new strategy which in fact primarily included a crackdown.
"That shows what their priorities were," she added, saying there was little in place for women once they had stopped working as prostitutes and no way of keeping tabs on them.
"On the face of it in Ipswich there are fewer women on the streets, but they don't know how long it will last, what the women are doing, and what has happened to all the women," she said.
Many of the women who had moved from Ipswich had gone to other areas, such as nearby Norwich.
She wants the government to follow New Zealand's lead where prostitution has been decriminalised, arguing women would be safer as they can report attacks to police, and clients themselves can go to the authorities without fear of criminal action.
Research by the New Zealand government due out soon was set to be extremely favourable with the conclusion the policy had not led to an increase in prostitution.
Experts agree that outlawing the trade could lead to more harm to sex workers.
"Academic research demonstrates that enforced treatment/ rehabilitation or criminalisation of sex workers (or their clients) is ineffectual at best, and more often dangerous," a dozen leading academics and researchers wrote in a letter to newspapers last month.
"Real political concern to support sex workers is being diverted and proper debate about the current proposals is being stifled by some fundamentalist and some radical feminist organisations interested in pursuing a moral crusade against purchasing sex."
Mitchell said whatever the government did, the world's oldest profession was not going to vanish.
"Men are not going to stop buying sex, it's just going to make it much more difficult and it's just going to drive it underground.
"It just drives it into the hands of gangsters."
