Taiwanese smartphone maker HTC has posted weaker-than-expected results for the first three months of 2015, while still managing to notch up a fourth successive quarterly profit.

HTC was once the star of the intensely competitive smartphone sector, but has seen its fortunes collapse in recent years as Samsung, Apple and strong Chinese brands like Lenovo and Huawei have surged ahead.

HTC said net profit came in at Tw$360 million ($11.6m) in January-March, a stark improvement from a net loss of Tw$1.88 billion in the same period last year.

Revenue rose 25% to Tw$41.52 billion from last year, when it hit a five-year low of Tw$33.1 billion, the company said in a brief statement.

However, both net profit and revenue fell compared to the previous quarter - HTC had posted Tw$470 million net profit and Tw$47.87 billion revenue in October-December.

"HTC's first quarter performance was pretty weak," said Jeff Pu, analyst at Yuanta Securities Investment Consulting.

"It only reported Tw$20 million in operating profit, which showed that its core business was not improving," he said.

The week-long delay in the launch of the new HTC One M9 smartphone in Taiwan, pushed back from the original mid-March date due to a software upgrade, had not helped matters, said Pu.

And even after the launch, demand had been disappointing, he said. 

"There is no significant difference in M9's design, appearance and functions, so the demand has not been strong," he said.

In the third quarter of 2013, HTC swung to its first net loss since listing in 2002, as it fell out of the world's top ten vendors.

Last year's launch of the popular M8 model created a fresh buzz around the brand, but analysts have warned that it still has a long way to go before regaining lost ground.

"The momentum of HTC One M8 did not continue to the first quarter, while sales of its mid-tiered phones were also unimpressive as Apple was too strong," said Wanli Wang, an analyst at CIMB Securities.