The move to send 1,000 more troops to join its existing 100-strong force came after Nato defence officials said over the weekend that they needed to add to the existing 20,000-strong force in the country to fight resurgent Taliban forces.
Leszek Laszczak, Poland's defence ministry spokesman, said the additional troops would be sent "from February".
He said, "We know this will be a dangerous operation. Poland understands that Nato will have to be more active in Afghanistan."
James Appathurai, a Nato spokesman, earlier said there had been "positive indications" from some allies that they might consider providing extra forces to help British, Dutch and Canadian troops locked in daily clashes with Taliban guerrillas, but did not provide further details.
In Canada, CBC television said Ottawa was about to send an additional 120 troops to the southern Kandahar region to boost the country's 2,300-soldier mission there.
A Canadian defence ministry spokeswoman said no formal decision had yet been taken.
US general James Jones, Nato's top commander of operations in Afghanistan, said last week he wanted up to 2,500 extra troops to join the fight against the Taliban.
He also called for additional helicopters and transport aircraft to help combat Taliban fighters in the south who are putting up a stronger resistance to the foreign forces than was originally anticipated.
Appathurai acknowledged countries would probably not finalise any offers before Nato defence ministers meet on September 28-29 in Slovenia and that any actual deployment could have to wait until October.
Nato nations currently have about 18,500 troops in Afghanistan.
Non-Nato countries also contribute a further 1,500 to its International Security Assistance Force (Isaf) based in Kabul.