Losses widened at Spotify, as the world's biggest music streaming service continued to invest heavily to fend off increased competition in the sector.

In the financial year to the end of 2015, the Swedish company saw users grow from 60 million to 89 million, with 28 million of them paying for subscription. However, losses widened 7% year-on-year to €173m (£134m, $194m) and the group, which was founded in 2008, has still to turn a profit. Spotify admitted the losses were largely driven by investments it made in a bid to fight off competition from the likes of Apple, Deezer, Rhapsody and Tidal.

There was however better news on the revenue front. In the 12 months to the end of last year, Spotify saw revenue surge 80% year-on-year to €1.94bn, as it outpaced the 45% gain recorded in 2014 and the 74% increase posted in the previous 12 months.

"In many ways, it was our best year ever," Spotify said in a statement.

"We believe that we will generate substantial revenues as our reach expands and that, at scale, our margins will improve. We will therefore continue to invest relentlessly in our product and marketing initiatives to accelerate reach."

Last month, Spotify came under scrutiny as hundreds of account details from users all over the world have been leaked on to the text-storing website Pastebin, including everything from usernames and passwords to email addresses and other details like the account type.

However, the company denied it had been hacked and stressed its user records remained safe. "Spotify has not been hacked and our user records are secure," a company spokesman said.

"We monitor Pastebin and other sites regularly. When we find Spotify credentials, we first verify that they are authentic, and if they are, we immediately notify affected users to change their passwords."