Siemoniak Monday also said that weapons deliveries might be on the agenda when Ukrainian Defence Minister Valeriy Heletey visits Poland this month, Xinhua reported.
On Sunday, Heletey said that a NATO country had agreed to sell weapons to Ukraine and that the delivery was already on its way.
"Ukraine's defence minister spoke clearly of one country that has started supplying weapons to Ukraine. That country is not Poland," Siemoniak said.
He added that he had said publicly before that Poland was open to selling arms to Ukraine.
"I expect talks to be held on this matter. I think the less said about these things, the better. These are matters to work on and not for media to speculate about," Siemoniak said.