The senior civil servant in charge of removing failed asylum seekers from Scotland has conceded his department is still not "fit for purpose".
Dawn raids have led to numerous protests in Scotland
Phil Taylor said it could be another 18 months before the Home Office's Immigration and Nationality Directorate (IND) was fully restructured.
Officials said that from now on there would be much stricter enforced removal of those who remained here illegally.
A number of failed asylum seekers have already been subject to dawn raids.
There are about 1,500 families, mostly in Glasgow, whose applications for asylum have failed but who still refuse to leave.
Following protests, a new system to deal with the removal of failed applicants has been launched.
Mr Taylor, who is regional director of the immigration and nationality department, said he was confident that with new resources in place and new rules, his office would be "fit for purpose" within 12 to 18 months, admitting this was not the case currently.
Ian Davidson, Labour MP for Glasgow South West, admitted there was a huge backlog of cases the system was failing to deal with.
He said: "I'd much rather not have the dawn raids but we're still awaiting somebody giving us a realistic alternative.
"People, by and large, who have come here claiming asylum falsely have lost their appeals, lost all the way through the process, taken things to judicial review, spent substantial sums of money on legal aid in many of these cases - and they still don't leave at the end.
"In those circumstances it's very difficult to see what other option we have."
Mr Davidson said it must also be recognised that there are substantial numbers of overseas students or visitors who overstay, claim asylum and then prolong that process.
Stewart Hosie MP, the Scottish National Party's spokesman on Home Office matters, said: "I have real concerns that the major upheaval which will occur when the Home Office itself is split might add uncertainty to the work under way in the IND.
"The home secretary now must give the people an assurance that progress to make the IND fit for purpose will not be hindered by any future changes in the Home Office"
Simon Hodgeson, head of policy at the Scottish Refugee Council, said people were genuinely scared about being returned to their countries and have felt unfairly treated by the system.
He said: "The new system is going to allow lawyers to represent them at the early stages, that wasn't the case in the past, so people had to present their case themselves."