Ash lead singer Tim Wheeler says Westlife are an "embarrassment" to Irish music.
He's told October's Q magazine he couldn't believe seeing a large billboard at Dublin Airport welcoming people to the home of Westlife.
He said they had a go at Westlife by burning 100 copies of their CD.
"I always make a big point of spitting at the billboard whenever we walk past," said Wheeler.
"They said we couldn't sell 250 records and then we came out with a platinum album, Free All Angels, that went to number 1," he added.
Asked how he would feel if Westlife burnt copies of Ash's new album, Wheeler said: "We'd appreciate the sales, especially if they were to do it in the first week of release."