Coalition forces did use cluster bombs in built-up areas during the Iraq war, but a concerted clean-up operation is under way, the government has said.
Cluster bombs are again provoking controversy
Defence Minister Adam Ingram was responding to increasing concern over the use of the bombs.
Seventy-five Labour MPs are calling for cluster bombs, which can leave unexploded "bomblets", to be banned because of the threat they pose to civilians.
Mr Ingram insisted they had been used in a targeted way against specific military targets.
That did include built-up areas where coalition troops had come under threat, Mr Ingram told BBC Radio 4's Today programme.
Defence Secretary Geoff Hoon on 3 April told MPs that cluster bombs were used only when it was "absolutely justified" because it would "make the battlefield safer for our armed forces".
With about a week of the war to go, Mr Hoon said it had "so far" not been necessary to use cluster bombs in Basra.
He said cluster bombs would injure civilians on occasions but such incidents would be kept to a minimum.
On Thursday, Mr Ingram appeared to suggest the weapons had been used in the southern Iraqi city.
He said: "We have a massive programme of education in Basra and those other areas where we have used such weapons."
The armed forces minister argued the use of cluster bombs had helped to prevent more coalition casualties.
He insisted the government had been consistent in its statements about when and where the weapons would be used.
"These are not illegal weapons. They are used in specific circumstances where there is a threat to our troops," he said.
"Now, clearly there were circumstances where there were concentrations of military equipment and Iraqi troops in and around built-up areas.
"Now, how were we to tackle those people. Were we to have close combat with them with more casualties on our side?"
Mr Ingram said it took time to identify unexploded bombs but there were 200 people working on the task.
Maps showing where the bombs were dropped had been issued, he said.
And 100,000 unexploded pieces of ordnance - not necessarily cluster bombs - had been destroyed in the region.
On 6 February, government spokeswoman Baroness Crawley told the House of Lords that the UK would "not countenance" the use of cluster bombs.
Mr Ingram stressed that Baroness Crawley was not a defence minister and argued it was Mr Hoon's statements which were important.
Labour MP Austin Mitchell is one of those backbenchers pressing for more action in clearing unexploded bombs.
He told Today: "Now that the search for weapons of mass destruction produced by Iraq is on and failing, nothing much is being done about the weapons of mass destruction used by our side, which are basically cluster bombs.
"Unless we clean up our own mess then our position is dishonest and contemptible. We should not use these weapons."
Each cluster bomb contains 147 bomblets - useful when tackling armaments spread over a reasonably large area.
With cluster bombs dropped from the air, 16% of those do not explode immediately, compared to a 2% failure rate for bombs launched from the ground.
Jo Nicholls, from charity Oxfam, said she had seen civilians hurt by cluster bombs in her visits of hospitals in Baghdad.
One man had told her how a bomb had exploded right in front of him as he stepped out of his house, "splitting him open" from neck to crotch, although he survived the blast.