The pipelines - billed as Beijing's "new strategic energy channels" - could be completed by May 30 and could become operational in early June, according to a top official.
"Construction has been sped up on the pipelines' domestic and overseas sections. Barring insurmountable barriers, the oil and gas pipelines could begin operating in early June," Gao Jianguo, the head of the project under the China National Petroleum Corporation (CNPC), told Xinhua news agency.
The main parts in Myanmar have been finished, while those in Chinese territory will be completed this month. The pipelines will undergo pressure tests and a drying process in February, Gao said.
Crude oil will be shipped from the Middle East via the Indian Ocean -- instead of the risk-prone Strait of Malacca -- before reaching Myanmar and entering China via the oil pipeline, the news agency reported.
The pipelines run from the port of Kyaukpyu on Myanmar's west coast and enter China at Ruili, Yunnan Province.
The oil pipeline has a designed annual transport capacity of 22 million tonnes, while the natural gas pipeline has a designed annual transport capacity of 12 billion cubic meters.
The channels will significantly increase the energy supply to the country's underdeveloped southwestern regions.