UPDATE 1-Taiwan's HTC Q1 profit, March sales rise

* Q1 unaudited net profit $158 million

* March sales rise 33 pct (Adds unaudited profit figure)

TAIPEI, April 6 (Reuters) - Taiwanese smartphone maker HTC (2498.TW) reported a rise first-quarter profit on Tuesday on an unaudited basis, above its own expectations, and said March sales jumped 33 percent over the same month a year earlier.

Unaudited net profit for the first quarter was T$5.03 billion ($158.5 million), above its own expectations in an illustration of the effectiveness of its brand strategy, it said in a statement. It did not give further details.

It had reported a net profit of T$5.579 billion in the fourth quarter and T$4.89 billion in the first quarter of the previous year.

Sales rose to T$16.383 billion for March, up from T$12.376 billion in the same month a year ago.

Last month its chief executive had said that first quarter sales would be better than expected, thanks to strong demand for smartphones.

HTC ranks behind bigger smartphone rivals Nokia Oyj (NOK1V.HE), Blackberry maker Research in Motion (RIM.TO), iPhone maker Apple Inc (AAPL.O) and Motorola Inc MOT.N in the global smartphone rankings, according to research firm IDC.

Earlier this month, Apple sued Taiwan-based HTC and accused it of infringing 20 hardware and software patents related to the iPhone.

The company's website is at www.htc.com/tw/