Home Office Minister Phil Woolas provoked outrage today after he claimed immigration officials were "putting their lives on the line" for the country.
Critics said it was "deeply insensitive" to compare desk-bound civil servants to heroic British troops.
His comments came as military chiefs prepared to name the 100th member of the Armed Forces to die in Afghanistan this year.
Mr Woolas said staff at the UK Border Agency were "very brave" as he sought to defend bonuses of £295,000 for senior officials.
Tory MP Patrick Mercer, a former British Army Officer said: "I think this is another extraordinary statement.
"It is a very hard thing to swallow for our fighting forces to be compared to an immigration service about which most of us have the gravest of doubts.
"It's deeply insensitive to make those statements the day after the 100th member of the Armed Forces was killed in Afghanistan this year."
Mr Woolas made the comments on the BBC Radio 4 Today programme following the publication of a highly critical report by MPs into the immigration system.
The Home Affairs Select Committee report said UKBA was still "not fit for purpose" years after revelations about foreign prisoners and the backlog of asylum claims.
Mr Woolas told presenter John Humphreys: "I think the UK Border Agency should be praised - they are very brave men and women who protect our borders and they are getting on top of the situation.
"The chair of the (Home Affairs) Select Committee has said we are not yet fit for purpose and I'm defending my staff who put their lives on the line for us."
The committee's chairman, Keith Vaz, said it was "astonishing" that bonuses were paid despite an embarrassing new discovery that officials had lost track of tens of thousands of immigrants.
Earlier this year officials admitted there were 40,000 cases, most more than six years old, where there was "no formal record" of whether immigrants had left the country.
Mr Woolas's comments follow an earlier gaffe when he claimed British troops were in Afghanistan in part to help control immigration into Britain.
Mr Woolas later issued a statement denying that he was comparing immigration staff to British troops in Afghanistan.
He said: "It is ridiculous and contemptible to suggest that I compared the immigration service to our soldiers serving in Afghanistan.
"UK Border Agency frontline officers work 24/7 at our ports around the country and posts abroad to protect our border, and in daily operations in partnership with the police to arrest and deport foreign criminals in often difficult and dangerous situations."
The report revealed that 29 senior UKBA staff were paid a total of £295,000 in 2007/8 - an average of more than £10,000 each.
Former Home Secretary John Reid said the immigration system was "not fit for purpose" in May 2006 after revelations about foreign prisoners not being deported.
Since the asylum backlog of 450,000 files was uncovered three years ago, 220,000 have been dealt with.
Some 74,000 asylum seekers and their children have been granted leave to remain and only 30,000 (14%) have been removed from the country.
Increasing numbers are being allowed to stay because as time passes with further delays they are more likely to have established a "family life" in the UK, the report said.
The committee called for the target of 2011 for officials to deal with the "substantial" asylum backlog to be moved to September next year.
Some have been living here for as long as nine years before being given a final decision, the report revealed.