Whether fighting will actually cease remains unclear, since the Kachin Independence Army has not yet made a similar declaration.
State television cited a statement from the government's information team saying the military will stop what it calls mopping-up operations in the area near its base at Lajayang at 6 a.m. Saturday (2300 GMT Friday). The army called on the Kachin to instruct their guerrillas not to launch attacks on government troops.
The army launched an offensive on Christmas Day after Kachin guerrillas rejected a demand they stop blocking government supply convoys.
The two sides have been fighting for 1 1/2 years, but the latest combat represented a major escalation because the government employed fighter planes and helicopter gunships in its attacks. Friday's declaration said air power was used to try to pinpoint attacks on Kachin military positions and avoid civilian targets.
The upsurge in fighting drew calls from the international community for the two sides to put down their arms and negotiate, but there was no public indication of any direct talks taking place.
Tension with ethnic minorities fighting for greater autonomy in Myanmar is considered one of the biggest major long-term challenges for reformist President Thein
The Kachin, like Myanmar's other ethnic minorities, have long sought greater autonomy from the central government. They are the only major ethnic rebel group that has not reached a truce with Thein Sein's administration.
A cease-fire that held for nearly two decades broke down in June 2011 after the Kachin refused to abandon a strategic base near a hydropower plant that is a joint venture with a Chinese company. The conflict has forced about 100,000 Kachin from their homes since then, and many are in camps near the Kachin headquarters in Laiza near the Chinese border.
The recent fighting flared up after the Kachin rejected a government demand that they stop attacking convoys delivering supplies to the army base at Lajayang. The guerrillas contended that the convoys carried ammunition that could be used to attack their own nearby Laiza headquarters. The government then launched its offensive to clear the road to its base.
Friday's government announcement said altogether 35 soldiers had died and 190 were wounded due to Kachin attacks on convoys. The total number of Kachin casualties is not known, though the group's supporters said it included civilians.
Friday's announcement cited Commander-in-Chief Vice Senior Gen. Min Aung Hlaing as saying the army was obeying Thein Sein's order of December 2011 to stop attacks against the Kachin except in self-defense, but that tensions could be reduced only when both sides stopped fighting, so the Kachin should also instruct their troops not to launch attacks. The general said that since December 2011, there had been 1,095 skirmishes with the Kachin, who also destroyed and damaged roads and rail lines.