Profits at China's major industrial firms maintained robust momentum in the first four months of the year despite mounting external uncertainties, with equipment manufacturing and high-tech sectors posting strong gains, official data showed on Wednesday.

In the first four months, industrial enterprises with annual main business revenue of at least 20 million yuan ($2.95 million) saw their total profits climb 18.2 percent year-on-year to 2.4358 trillion yuan, 2.7 percentage points faster than the growth recorded in the first quarter, data from the National Bureau of Statistics showed.

In April alone, major industrial firms posted a 24.7 percent year-on-year increase in profits, compared with 15.8 percent growth in March, the NBS said.

The strong performance in industrial profits, according to Yu Weining, a statistician with the bureau, was underpinned by more proactive macroeconomic policies.

"With more proactive macroeconomic policies effectively implemented, industrial production kept growing at a relatively rapid pace and industrial product prices continued to recover, thereby driving faster growth in industrial profits," Yu said.

Notably, strong gains in equipment manufacturing and high-tech sectors showed that new growth drivers played a key role in driving the improvement, signaling continued improvement in industrial firms' profitability, Yu said.

NBS data showed that profits in the equipment manufacturing sector grew 15.4 percent year-on-year in the first four months, contributing 5.4 percentage points to overall profit growth among major industrial firms. Meanwhile, profits in high-tech manufacturing jumped 44.8 percent, contributing 7.8 percentage points to overall industrial profit growth.

The raw material manufacturing sector also saw profit growth gather pace. Profits at major firms in the sector surged 88.1 percent year-on-year in the first four months, accelerating by 10.2 percentage points from the first quarter and contributing 10.3 percentage points to overall profit growth.

In the first four months, mining firms posted a 26 percent year-on-year increase in profits, while manufacturing companies recorded 20.4 percent growth. Profits at firms supplying electricity, heat, gas and water declined 1.9 percent, the NBS said.

Despite the strong profit gains, Yu cautioned that the external environment remains volatile, with the domestic imbalance between strong supply and weak demand still prominent and some enterprises continuing to face difficulties in production and operations.

Looking ahead, Yu called for stronger macroeconomic policy support to further expand domestic demand and optimize supply, in order to support the sustained and healthy development of the industrial economy.