Deputy Defence Minister Janusz Zemke told the International Herald Tribune in an interview published on Monday that his country's troop contribution to Iraq has prevented it from financing modernisation of its armed forces.
Poland is the fifth-largest troop contributor to the US-led forces in Iraq after the US, Britain, Italy and South Korea.
Other countries in the "coalition of the willing" which sent small numbers of troops to Iraq had received similar funding to that of Poland, Zemke complained.
Zemke said he had raised the issue of financing with the Pentagon. He said he was concerned that Poland received the same funding as countries with much smaller troop contingents.
"We simply will not be able to squeeze more of our own budget for military procurement," he said.
"At the same time, these huge outlays for Iraq are delaying the final transformation of our armed forces. It is a fundamental problem."
The Polish defence official's comments come as tensions grow between Warsaw and the Bush administration over Poland's publicly voiced intention to pull its troops from Iraq.
Now running neck-and-neck in the polls against Democratic challenger John Kerry ahead of 2 November elections, US President George Bush in the first of their televised debates specifically mentioned Poland when accused of failing to rally international support for the US-led invasion of Iraq.
Bush is under fire for not getting
international support for the war
But Polish leaders later said they aimed to take their troops out of Iraq by the end of 2005, and Prime Minister Marek Belka promised on Friday that Polish soldiers would not stay "an hour longer than needed".
Just hours before a confidence motion in parliament that his shaky left-wing government narrowly survived, Belka promised that Poland would start a progressive withdrawal early next year.
The decision to send Polish troops to Iraq last year was supported by public opinion but, amid persistent unrest in the country, polls now show that more than 70% of the population want them back home.
Zemke said Poland had received $27 million last year from the US in military aid after supporting the US-led operation in Iraq.
This annual aid rose recently to $66 million, but is still less than the $100 million Poland spends a year in Iraq, excluding costs for sending and maintaining equipment.