Earlier this month, Britain postponed plans to pull up to 1,500 troops out of the war-torn country due to unrest in the southern city of Basra.
"While the situation on the ground continues to evolve rapidly, and while military commanders continue to assess the changing environment in Basra, it remains prudent that we take time to fully consider further reductions," Des Browne told parliament.
He reiterated that any reductions to Britain's 4,000-strong contingent will only be made when security improves.
"It remains our clear direction of travel and our plan to reduce our force levels, as and when conditions allow, from the current number," he said.
Britain had previously intended to cut troop numbers to 2,500 during spring
The approximate total deployment of the U.S.-led coalition force in Iraq is around 166,000 troops.
About 4,000 American soldiers, and up to 90,000 Iraqi civilians (according to the Iraq Body Count project) have been killed in Iraq since the invasion by U.S.-led forces in 2003.
One hundred and seventy-six British soldiers so far have died in Iraq.
