The company which invented thalidomide has "insulted" those affected by the drug by issuing an "insincere" apology, campaigners have said.
The drug, sold in the 1950s as a cure for morning sickness, was linked to birth defects and withdrawn in 1961.
German-based Gruenenthal has issued its first apology in 50 years, but said the drug's possible side-effects "could not be detected" before it was marketed.
But the UK's Thalidomide Trust said any apology should also admit wrongdoing.
Nick Dobrik, a member of the trust's national advisory council, said it "should be an unreserved apology, not a conditional apology".
"We feel that a sincere and genuine apology is one which actually admits wrongdoing. The company has not done that and has really insulted the thalidomiders."
Martin Johnson, the trust's director, told the BBC that the news that the manufacturers were starting to acknowledge responsibility was welcome but they were still trying to perpetuate the myth that no-one could have known of the harm the drug could cause when there was, he said, much evidence that they did know.
And Freddie Astbury, president of Thalidomide UK, said: "It's taken a long time for them to apologise. There are a lot of people damaged by thalidomide struggling with health problems in the UK and around the world.
"So we welcome the apology, but how far do they want to go? It's no good apologising if they won't open discussions on compensation. They've got to seriously consider financial compensation for these people."
By the time the drug was pulled from the market, more than 10,000 babies worldwide had been born with a range of disabilities caused by the drug.
This included shortened arms and legs, blindness, deafness, heart problems and brain damage.
There are between 5,000 and 6,000 sufferers still alive. Thalidomide UK says there are 458 people in the UK who were affected by the drug, but that for every thalidomide baby that lived there were 10 that died.
Harald Stock, Gruenenthal's chief executive, issued his company's apology at the unveiling of a bronze statue symbolising a child born without limbs because of thalidomide.
"We ask for forgiveness that for nearly 50 years we didn't find a way of reaching out to you from human being to human being," he said at a ceremony in the western German city of Stolberg, where the firm is based.
"We ask that you regard our long silence as a sign of the shock that your fate caused in us."
Mr Stock said the company regretted that the potential for thalidomide to affect the development of foetuses "could not be detected by the tests that we and others carried out before it was marketed".
BBC science correspondent for the Today programme, Tom Feilden, said one of the main issues was what Gruenenthal knew about the drug's side effects, when it knew about them and whether the company could have acted sooner in withdrawing it from the market.
Some compensation has been paid, particularly by thalidomide's British distributor.
Gruenenthal itself has previously paid compensation to survivors of the drug, many in Germany, and has voiced regret over the issue - but has not admitted liability.
In the early 1970s, it agreed to pay 100m Deutschmarks (£40m) into an official fund for German thalidomide survivors and was given permanent legal indemnity by the German government.
Since the original fund money ran out, continuing compensation payments have been made by the government. In 2009 the company added a further 50m euro (£39.6m) one-off endowment.
Compensation claims are still outstanding, including one key class action in Australia, which saw thalidomide survivors win the right to have their case for compensation heard there.
The drug is still used today under strict controls to treat some bone marrow cancer patients.