Poland's foreign minister has attacked some Nato members for not committing enough troops to Afghanistan.
There are concerns that the mission may be failing
Radoslaw Sikorski said he would commit Polish troops and helicopters to assist Canadian soldiers in Afghanistan.
His criticism comes amidst warnings from Canada that it will pull out its troops from Afghanistan unless Nato reinforcements are sent.
Nato has 40,000 troops under the International Security Assistance Force (Isaf) in Afghanistan.
Mr Sikorski made his remarks on a visit to the Canadian capital, Ottawa.
He offered strong support to Canada in its bid to have more Nato troops to be sent to Kandahar in the restive south of the country.
But he said it was unacceptable that a gap in Nato's ability to send troops there had been created by some members unwillingness to do so.
"More needs to be done, the burdens have to be shared more fairly and there's no room for free riding in this most important of operations that Nato has ever undertaken," Mr Sikorski said.
He did not identify the countries by name, but many Nato allies with troops in Afghanistan have stationed them in relatively quiet areas in the north of the country.
The United States, Britain, Canada and the Netherlands are the main countries involved in counter-insurgency operations against the Taleban, in the south.
Poland has 1200 troops stationed in Afghanistan and plans to send another 400 this year.
Mr Sikorsky said he is willing to share some soldiers and helicopters with the Canadians.
"When an ally asks you, you try to accommodate him. This mission has to be a success and can only succeed by doing it together," he said.
Canada served notice last month that it would withdraw its troops early next year unless Nato sends at least 1,000 extra troops to bolster its mission in Kandahar.
Correspondents say there is are growing signs of strain in the Isaf mission in Afghanistan and in Nato as a whole.
Last week, Germany has rejected a US appeal to send more troops to Afghanistan.
The US has already promised to send an extra 3,000 marines - but is urging other Nato countries to do more amid rising Taleban attacks.
The issue of troop commitments will be the most urgent matter before Nato leaders at a summit in Bucharest in early April.