Minister Pavithra Waniarachchi illuminated the sacred temple town of Anuradhapura with 4,000 coconut oil lamps seeking divine help to end the drought and offered alms to local monks on Monday.
She also offered a pot of water to Buddhism's holiest tree, the Sri Maha Bodhi, in the north-central temple town of Anuradhapura as a symbol of her faith.
"She took a pot of water from a hydro-reservoir which had hit rock bottom and offered it to the Bo tree (Sri Maha Bodhi)," her spokesman Sisira Wijesinghe told AFP. "The hope is that there will be rains soon."
Sri Lankans seek blessings from the tree at times of crisis.
Prolonged droughts often result in electricity outages as the country's thermal power stations struggle to meet demand.
Wijesinghe said reservoirs had dropped to less than 25 percent of their capacity due to a prolonged drought.
Sri Lanka suffered a major drought 10 years ago prompting water rationing and electricity cuts.
