In a live television interview on Sunday, Kwasniewski said Warsaw could not allow troops to withdraw "unilaterally, nervously and in disarray".
When confronted by the interviewer with poll results showing 73% of Poles opposed their country's military involvement in Iraq, Kwasniewski said Poland would lose its international credibility if it pulled out in an irresponsible manner.
He was speaking hours after three Polish soldiers died and three others were wounded in an ambush near the Iraqi city of Hilla. That brought Poland's toll in Iraq to 17.
A Polish sapper patrol, called in to disarm a booby trap by the side of the road, came under machine-gun and mortar fire.
Poland commands a multinational force of 8000 troops including about 2500 Polish soldiers in Iraq's south-central region.
But Kwasniewski did reiterate that Poland wanted to downscale its military presence and would discuss the issue with Iraqi President Ghazi al-Yawar, who starts a two-day visit to Warsaw on Monday.