* Q1 net down 70 pct, just below forecasts

* But March sales revenue picks up from February

* March pick-up could point to a better Q2 - analyst

* Rival Samsung reports record Q1 profit

TAIPEI, April 6 (Reuters) - Taiwanese smartphone maker HTC Corp reported a 70 percent tumble in net profit in the first quarter, just below forecasts, in a lean period for the company ahead of its new One series of models that are set to hit the market this month.

HTC is banking on those models to regain market share lost to Apple Inc's iPhones and Samsung's Galaxy range at the end of last year, when its sales slumped and investors dumped its shares on concerns the firm had lost its edge.

But in a sign of a pick-up, it also reported on Friday that consolidated sales for March were T$30.879 billion, up from February's T$20.29 billion though still down 16.62 percent from the same month a year earlier.

"March revenue rose, and if it can keep up the trend seen in March, we would expect to see a pretty strong Q2," said Bonnie Chang, analyst at Yuanta Securities.

"Revenue could rise 40 percent over Q1, and with the traditionally stronger season in the second half, HTC could continue to see sequential growth in H2."

The world's No.5 smartphone maker's unaudited net profit in the quarter was T$4.464 billion ($151.50 million), compared with T$14.83 billion a year earlier and T$10.94 billion in the previous quarter, it said on Friday.

A poll by Thomson Reuters I/B/E/S of 19 analysts had yielded a median forecast of a profit of T$4.56 billion. The company did not elaborate in its brief statement on Friday. It will brief investors on the results later in the month.

First-quarter revenue fell to T$67.79 billion from T$104.157 billion a year earlier.

That was within the company's forecast earlier this year of a drop in revenue of as much as 36 percent in the first quarter to between T$65 billion and T$70 billion from the previous three months as it prepared to launch new models.

It said at the time its difficulties were "short term" as it fought perceptions that it no longer had the innovative skill that had propelled it from obscure contract maker to must-have device brand.

In late February, HTC announced its One series of models with fast graphic chips and advanced music and photography functions. The series received generally positive reviews from analysts and tech bloggers and is set to hit the market this month.

But it still faces a tough challenge, with Apple set to launch a new version of the iPhone this year and new offerings from Samsung, which posted a record quarterly profit on Friday driven by booming sales of its smartphones and the Galaxy Note 'phablet'.

"Of course it is very difficult to expect HTC to compete with Apple or Samsung, the market share gap is too big," said Yuanta's Chang.

"But if it could catch up with RIM or Nokia, then it's pretty good."

According to technology research firm IDC, HTC had 8.9 percent of the global smartphone market in 2011, well behind Samsung's 19.1 percent and Apple's 19 percent, but closing in on troubled Blackberry maker Research in Motion's 10.4 percent.

On Friday, ahead of its earnings announcement, HTC closed up 2.8 percent at T$585.0, versus the broader market's 0.87 rise. (Reporting by Clare Jim and Argin Chang; Writing by Jonathan Standing; Editing by Matt Driskill and Jacqueline Wong)

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