The Chinese economy expanded 6.4 percent year on year in the first quarter of this year, official data showed Wednesday.

China's GDP reached 21.343 trillion yuan (about 3.18 trillion U.S. dollars) in the first three months of 2019, and the growth pace was the same as that of Q4 2018, the National Bureau of Statistics (NBS) said in a statement.

The tertiary sector reported the strongest growth in added value by expanding 7 percent to reach 12.232 trillion yuan, which accounted for 57.3 percent of the total Q1 GDP, picking up by 0.6 percentage points compared with Q1 2018.

Consumption continued to be the mainstay in driving up demand, contributing 65.1 percent to Q1 economic growth, NBS data showed.

The industrial and agricultural sectors saw their added value grow 6.1 percent and 2.7 percent respectively.

Wednesday's data also showed stable Q1 growths in fields including industrial output, retail sales, property investment and resident disposable income.

The national economy performed within an appropriate range in Q1, sustaining the momentum of progress in overall stability with growing positive factors, which laid a sound foundation for the stable and healthy economic development of the whole year, the NBS statement said.

A string of economic data have shown notably improved market expectation with strengthened development confidence.

Factory activities became expansionary in March after staying below the threshold for three months, while the services sector continued to expand. The Q1 Consumer Confidence Index was 3.2 percentage points higher than that of Q4 2018.

The NBS also pointed out that the task of reform and development is arduous and the economic downward pressure still persists given global uncertainties and domestic structural issues.

The government will fully mobilize the initiative of all sectors of the society, and redouble efforts to implement policies to ensure the economy performs within an appropriate range and advance the high-quality development, the NBS said.