Officials on Thursday said the separatists carried out the attacks in violation of their pledge not to attack the country's infrastructure.
Defence ministry sources said 11 Maoist fighters were killed in several armed encounters with the army and police over the last two days.
The Maoists also shot and killed a trader in Birgunj town, about 220km south of capital Kathmandu.
They also bombed and destroyed the home of Culture, Tourism and Civil Aviation Minister, Sharbendra Nath Shukla.
"A group of 14 Maoist rebels travelling on bicycles forced all the family members of the minister out of the house situated at Pharena village in western Nepal and planted a powerful cooker bomb inside," a government spokesman said.
A 200-kilowatt micro hydropower project was also bombed by the separatists in western Bajura district, leaving 500 households without electricity.
"A group of 10 armed Maoists attacked the power plant, completely damaging important equipment," a military spokesman said.
The fresh round of attacks came despite Tuesday's announcement by Maoist Chairman,Pushpa Kamal Dahal that the outfit would not attack infrastructure or carry out political killings.
The Maoists have been battling government forces since 1996, seeking a change in the country's constitutional monarchy.
The resultant conflict has claimed more than 8200 lives so far.