We describe a theoretical proposal of a nanofibre-based trap for a Rb2 molecule prepared in the metastable state (1)3Σu+. The trapping potential results from the combination of a travelling and a standing-wave fields, both carried by the fundamental guided mode HE11 of the fibre. We show that, with an experimentally realistic choice of laser frequencies and powers, one can implement a ≈200μK-deep well at ≈140 nm from the fibre surface accomodating for ≈500 translational molecular states