Holding parliamentary elections two years early has become increasingly likely since bitter fighting erupted within the fractious coalition between the ruling Kaczynski twins and volatile leftist and far-right allies.
Roman Giertych, the deputy prime minister and leader of the league, is among the dismissed ministers.
The three other ministers were charged with construction, labour and fisheries. New ministers were appointed immediately.
The Kaczynski twins have governed during a spell of fast economic growth but have failed to quell constant political infighting and squabbled repeatedly with other European Union leaders.
Their Law and Justice party gave its approval on Saturday for holding early parliamentary elections and the prime minister suggested that they could be held in October or by November at latest.
But an early election is a big gamble for the Kaczynskis, whose party is trailing in opinion polls behind the pro-business opposition Civic Platform, which favours quicker progress towards adopting the euro currency.
Jaroslaw Kaczynski made clear that his party is preparing to stay in power after elections and said the newly appointed ministers would contribute to success at the next elections.
"I hope these ministers will work in a way which will allow this government to continue its mission after elections," he said.
Poland plunged into crisis a month ago when the prime minister dismissed Andrzej Lepper, the deputy prime minister, who is the leader of the Self-Defence party.