The new government said it would end the detention of children at Dungavel
Children of asylum seekers continue to be held at the Dungavel detention centre despite a coalition promise to end the practice.
A Pakistani woman, Sehar Shebaz, and her eight-month-old daughter Wanya were detained after reporting to officials in Glasgow on Monday.
A spokesman for the immigration minister Damian Green said the current system must stay in place for now.
He said the Home Office had to consult on a replacement.
Mr Green said: "Our coalition government is committed to ending the detention of children for immigration purposes.
"I hope that we can have plans agreed within the next few months. Whilst this immediate review is ongoing, current policy remains in place."
He said he was launching a comprehensive review of alternatives to child detention and would be speaking to relevant stakeholders, organisations and experts.
"This work has already started, because it is in all our interests, including those children currently in detention, to do it quickly, but to also do it well and safely," he said.
"While keeping children's welfare at the heart of what we do, our government is committed to returning those with no right to stay in the UK."
SNP MSP Christina McKelvie said: "Last week the Lib Dems claimed the detention of children at Dungavel had ended.
"Tonight an eight-month old baby is being held behind bars in Scotland in contrast to the claims of Lib Dems last week.
"Children should not find themselves behind bars in a humane immigration system and if the Lib Dems deal means anything Danny Alexander and Tavish Scott must act to ensure this child, and all others are not detained in Dungavel for one more day."
Last week, Scottish Liberal Democrat leader, Tavish Scott, described the detention of children at Dungavel as "shameful" and hailed the Conservative/Lib Dem coalition's commitment to bringing it to an end.