Around 60 women have marched on private cosmetic clinics that fitted now-banned PIP breast implants, as an NHS media campaign set out government advice.
Marchers in London called on clinics to replace PIP implants free of charge.
Some clinics blame poor regulation for the use of the substandard implants and say they cannot afford to remove them.
NHS adverts in national papers repeated the message there was no evidence they were riskier than others but said the NHS would replace any it had implanted.
The now-closed French company Poly Implant Prostheses (PIP) filled its implants with industrial grade - rather than medical grade - silicone. It was originally manufactured for use in the mattress industry.
Around 300,000 of the PIP implants were sold around the world, mainly in Europe, with 40,000 fitted in the UK.
French, German and Dutch health authorities have all recommended that women fitted with PIP implants should have them removed as a precaution.
However, the UK government advertisement published in English newspapers on Saturday repeated its position that there was no need for routine removal.
In cases where implants were fitted privately, ministers have said only that the NHS will remove them. Replacements will only be funded if a patient's GP deems it "clinically necessary".
The chief medical officer, Prof Dame Sally Davies, said the government had already been issuing the advice through a number of sources.
"What we're doing... this weekend is making sure the clarity of the information, with the advice from an expert group involving plastic surgeons, is out there for the whole population to see."
BBC correspondent Richard Lister says Saturday's protest in London was small but passionate. He says the women all believed they had been let down by the private clinics and by a government that would pay to remove the implants but not to replace them.
He says the women were not reassured by the NHS newspaper advertisements.
The marchers began their protest at the headquarters of the Harley Medical Group, which installed some 13,900 PIP implants between September 2001 and March 2010.
The company has blamed the government's regulatory authority for approving the PIP implants. It accused the Medicines and Healthcare products Regulatory Agency (MHRA) of not carrying out proper checks.
Protester Mia Wood, 32, from Doncaster, South Yorkshire, told the Press Association: "I'm angry, I'm frustrated, I'm crying every day.
"They are so happy to take our money but not prepared to help support us."
Ms Wood said the women wanted their implants to be replaced by the private clinics that fitted them rather than the NHS because "we've paid for a service".
Stacey Williams, 25, from Portsmouth, said that some clinics had gone into liquidation and reopened under a different name since fitting the implants.
"They say because they are a different company we aren't covered any more," she said.
Before participating in the protest, Gemma Pepper told the BBC she felt that the government's advertisement showed that it was "still pretty much sitting on the fence".
"And as long as they say they're not dangerous, the clinics are gripping hold of that and sticking to it like glue basically, because they are refusing... to do anything at all as long as the government continues to say this."
Europe-wide regulation
The European Commission says the implant scandal "reinforces" the need to reform Europe-wide regulation.
Breast implants in Europe are regulated by the 2007 directive on medical devices. The commission has been reviewing the rules for the past three years and is due to give its recommendations this year.
Cosmetic surgeons have called for more spot checks and a register of all devices implanted into the body, and the commission is expected to recommend tougher rules.
There are more than 10,000 medical devices ranging from class I devices such as plasters, class IIa and IIb which include X-ray machines and class III, such as breast implants, pacemakers and hip replacements.
Frederic Vincent, health and consumer policy spokesperson for the European Commission, told the BBC: "It [PIP] reinforces our opinion that we have to be tougher on medical devices, particularly class III."
However, he added: "We are dealing with a case of fraud. It means that what happened in France could have happened even with a more stringent pre-market assessment of the products."
The formal proposals will be sent to the EU Parliament and the Council of Ministers for approval. However, it could take up to three years before they are adopted by member states.
source: bbc.co.uk
