Chinese e-commerce giant Alibaba Group Holding Ltd is freezing hiring for the rest of the year because it has grown "too quickly", Executive Chairman Jack Ma told staff.

"Alibaba has really developed too quickly ... this year our entire group headcount will not go up by one person," Ma said, according to a transcript of the April 23 speech carried on Alibaba's official messaging app Laiwang.

He, however, said the company will replace employees who leave. "When one leaves, we'll bring one in," Ma added.

The hiring freeze came to light about a week ahead of Alibaba is due to report March quarter earnings on May 7. In January, Alibaba, which handles more online commerce than Amazon.com Inc and eBay Inc combined, reported slowing revenue growth.

Headcount had been growing quickly at Alibaba. As of Dec. 31, 2014, the company had 34,081 employees, a 63 percent increase from a year earlier, the company said in January.

As long as gross merchandise volume was under 10 trillion yuan ($1.6 trillion), headcount should be below 50,000, Ma said. A headcount of "over 30,000" was already enough for now, he added.

Gross merchandise volume in the quarter to Dec. 31, 2014, was 787 billion yuan, a 49 percent increase from the same quarter the year before. For the whole year, it totaled about 2.3 trillion yuan.

Ma also that Alibaba would consolidate its businesses into seven segments - e-commerce, Ant Financial, Cainiao logistics, big data and cloud computing, advertising, cross-border trade and other internet services.