Sina Weibo, China's No 1 micro-blogging platform, which is preparing a Nasdaq initial public offering this week, reported a larger first-quarter net loss than a year ago.

The Chinese version of Twitter said its net loss was $47.4 million during the first three months of this year. The amount was $19.2 million during the first three months of last year.

The Sina Corp-backed website is overshadowed by accusations of a user number plunge since late last year as Tencent Holdings Ltd's instant messaging application WeChat quickly gained ground.

Last week, Hong Kong-based newspaper South China Morning Post reported that Weibo might have roughly 300 million "skeleton accounts". The total number of Weibo accounts is around 500 million.

Weibo announced on Tuesday its quarterly active user number was 143.8 million, with the daily active number hitting 66.6 million. The quarterly active user number was less than 130 million during the first quarter of 2013, it said.

More than 70 percent of active users have logged on to Weibo at least once each month using mobile devices, the company added, indicating a strong shift to the mobile Internet market.

Weibo has said it intends to raise up to $500 million in the IPO.