The Government's immigration policy was likened to President Donald Trump's as ministers revealed 44 children were currently being held in detention centres.
The Home Office was branded "cruel" as Immigration Minister Caroline Nokes told MPs the number of children detained stood at 44.
Labour MP Mary Creagh, who has consistently pressed on the issue, called on ministers to "get a grip" and end the "unlawful practice".
Ms Creagh, speaking in the Commons, raised the case of an Indian national who received £50,000 in damages from the Government after being placed in an immigration detention centre and unlawfully separated from his three-year-old daughter.
The man was detained under immigration powers in June 2017 after serving a 20-month prison sentence for unlawful wounding.
The child, an EU national, was placed in care during his jail term, but had been in regular contact with her father.
Ms Creagh said: "Despite compelling evidence of the harm caused to children by the indefinite detention of their parents the Home Office continues to separate them in an arbitrary and cruel manner.
"What is she doing to get a grip on the situation, stop this unlawful practice, tell us how many children are affected and reunite them with their families?"
Ms Nokes told MPs that the "welfare and safeguarding of children is at the heart of the family returns process", adding: "Other than in exceptional circumstances a child will not be separated from both parents for immigration purposes, detention is used sparingly for the purposes of public protection and removal."
Addressing the case of the Indian national Ms Nokes added: "The Home Office acknowledged its mistakes and indeed paid compensation, it is worth remembering of course that in 2009 more than 1,000 children went into detention, whereas the last year for which there are figures available it was only 44."
Shadow immigration minister Afzal Khan later added: "The Prime Minister has condemned Trump's family separation policy, but this Government's hostile environment separates parents from their children everyday."