  In this note, we prove that every even regular multigraph on $n$ vertices
with multiplicity at most $r$ and minimum degree at least $rn/2 + o(n)$ has a
Hamilton decomposition. This generalises a result of Vaughan who proved an
asymptotic version of the multigraph $1$-factorisation conjecture. We derive
our result by proving a more general result which states that dense regular
multidigraphs that are robust outexpanders have a Hamilton decomposition. This
in turn is derived from the corresponding result of K\"uhn and Osthus about
simple digraphs.
