The 'You Raise Me Up' singers are due to take a break of up to two years following the release of their Greatest Hits album in November.
The Irish boyband are aiming to record an 11th studio album when they return, according to The Mirror.
"The boys are pretty knackered," a source said. "They've been constantly working for the past decade and just want time to enjoy what they've made for themselves before coming back with a brand-new album."
The insider insisted: "They're not splitting up - it's a break. The plan is to come back with full force after that."
Westlife last month flew to South Africa to film the video for their upcoming single 'Lighthouse'. The track was written by X Factor judge Gary Barlow and has been described as "a really fitting lead" into their Greatest Hits LP.
The foursome will face a chart battle with One Direction upon the release of the retrospective.
Watch Westlife in the video for 'Safe' below: