Human rights groups have warned UK ministers against weakening protections against torture or other mistreatment for asylum seekers before a crucial European summit this week on how to respond to migration.

David Lammy, the justice secretary, is expected to help lead arguments at the Council of Europe meeting on Wednesday on how the European convention on human rights (ECHR) could be reinterpreted to limit the scope of rights under article 3, which prohibits torture and “inhuman or degrading treatment”.

The UK is also among countries who wish to push for similar changes of approach towards article 8 of the convention, related to the right to a family life.

As part of a significant toughening up of UK asylum policy announced last month, the Home Office said the balance between the rights of migrants under article 8 and the public interest of removing people from the country needed to be “fundamentally reset”.

The same document also signalled the UK’s intent to move on article 3, saying that while people should never face torture, the legal interpretation of inhuman or degrading treatment “has been expanded over time”, allowing people to block deportations on the basis of arguments such as the fact they could not receive proper mental healthcare in their own country.

While there is no plan for the Council of Europe to amend the ECHR, the way it is interpreted could be changed, for example through a declaration.

It is understood that while Wednesday’s meeting was originally expected to discuss matters only in relation to article 8, efforts by the UK and Belgium mean changes connected to article 3 could also be discussed.

Natasha Tsangarides, the associate director of advocacy at the charity Freedom from Torture, said it was vital for Lammy to “make sure that any rethink of article 3 does not lead to a watering down of the absolute ban on torture”.

She said: “Anything less would betray both the UK’s own history in forging that ban and the countless survivors of torture who rely on it. Torture is one of the most appalling violations imaginable and for centuries the UK has been a strong voice against it.

“If the government takes even small steps towards weakening article 3 protections, it risks setting off a chain reaction that could trigger a domino effect around the world. That cannot be allowed to happen. Human rights must be universal – either we all have them, or none of us do.”

Steve Valdez-Symonds, Amnesty International UK’s refugee and migrant rights director, said: “The threat to return people to countries they fled knowing it could put them at risk of torture, inhuman or degrading treatment or punishment, or result in them being unjustly separated from their family will undermine the basic principles that protect us all – not fix the immigration system.

“These vital protections under the ECHR must not be weakened, ‘rebalanced’, opted out from, or reinterpreted to suit political convenience. Once you strip rights from one group, everyone’s rights are put at risk, which is how universal protections begin to rot.”

A UK government spokesperson said: “We have been clear that the UK is committed to the European convention on human rights and we do not need to withdraw to deliver meaningful reform.

“The government’s immigration white paper sets out new plans to tighten the application of article 8 of the ECHR – giving courts the clarity they need so our immigration rules are no longer abused.”