SHANGHAI/SINGAPORE (Reuters) -Chinese stocks tumbled on Wednesday alongside their Hong Kong peers, as investors sought to profit from a blistering rally, which was dampened by the lack of powerful stimulus measures to revive the economy.

Benchmark indexes in China notched their biggest daily losses since the COVID-19 pandemic began, despite the announcement of a finance ministry press conference on Saturday to detail plans on fiscal stimulus.

The Shanghai Composite index slid 6.6% to 3,258.86 points, while the blue-chip CSI300 index declined 7.1% to 3,955.98 points. Both indexes booked their biggest one-day losses since Feb 2020 and also snapped a 10-day winning streak.

The smaller Shenzhen index ended down 8.65% and the start-up board ChiNext Composite index slumped 10.59% to post its biggest one-day loss on record.

Turnover in the A-share market, comprising stocks listed in Shanghai, Shenzhen and Beijing, was 2.96 trillion yuan ($419.04 billion) on Wednesday, down from a record of 3.485 trillion yuan a day earlier.

Market analysts said officials fell short of delivering further details of Beijing's massive stimulus measures at the highly anticipated National Development and Reform Commission (NDRC) press conference on Tuesday, leaving investors disappointed.

"I would say the NDRC's recent announcements were a bit disappointing, mainly because there wasn't much in the way of new stimulus or clear forward guidance," said Nori Chiou, investment director at White Oak Capital.

However, he said Wednesday's pullback in stocks was hardly a letdown for many, given their strong run over the previous sessions.

Hong Kong's Hang Seng index similarly ended 1.4% lower at 20,637.24 points, though it remains one of the region's best-performing markets this year following its steepest rally in a generation over recent weeks.

The Hang Seng Mainland Properties Index slid 3.27%, while technology shares shed 1.17%.

"The market is widely anticipating a fiscal stimulus announcement sometime this month, something like 2-3 trillion yuan is the range being talked about," said Alvin Tan, head of Asia FX strategy at RBC Capital Markets.

"The positive sentiment on China assets lately is premised on expectation of a major fiscal stimulus package, so that sentiment will turn quickly if we don't get some package at least matching the range above."

Tourism shares were among the top losers on Wednesday, as data showed that spending during the Golden Week holiday was yet to recover to pre-COVID levels. An index tracking the performance of the sector lost 8.97%.