The holiday photos look like two young women on a dream trip cruising around the world, not two alleged drug mules working for an international drug syndicate.

Seven weeks ago, Canadian national Melina Roberce made a gloating post on social media from Toronto airport as she was about to fly to the UK.

"Let's do it again .... #london." she captioned a photo of her passport and boarding pass that she posted on Instagram.

Over the next seven weeks she made more than two dozen posts of her and her travelling companion Isabelle Lagace, 28, while they were aboard the cruise ship the Sea Princess.