LONDON (AFP) - British rock group Queen is to release new tracks featuring Freddie Mercury's vocals by the end of the year, guitarist Brian May said.

The songs, dating back to the 1980s, will be released on a compilation album, May told BBC radio.

Mercury died of AIDS-related pneumonia in 1991. Four years later, Queen released "Made In Heaven," their final studio album with the iconic frontman, painstakingly constructing some fresh songs from lines of vocals he left behind.

But May said more tapes in the vault had come to light.

"We found a few more tracks with Freddie singing and all of us playing, and they're quite beautiful, so people will be hearing this work towards the end of the year," the 66-year-old said.

"We're going to put out an album which probably is called 'Queen Forever', and it's a compilation, but it will have this new material on which nobody in the world has ever heard. And I think people will really enjoy it."

In their current form, the songs do not have the bombastic Queen sound, but May and drummer Roger Taylor -- bassist John Deacon retired in 1997 -- are giving them the band's trademark anthem touch.

"Most of it comes from the 80s when we were in full flight, so it's quite emotional. It's the big, big ballad and the big, big kind of epic sound.

"It wouldn't have been if we hadn't done this restoration job on it because you have to start from scratch really, because we only had scraps.

"But knowing how it would've happened if we'd finished it then, I can sit there and make it happen, with modern technology."

May is also working up some rough tracks that Mercury recorded with Michael Jackson in 1983.