  Let $(E,h)$ be a semipositive hermitian holomorphic line bundle on a compact
complex manifold $X$ with $\dim X>1$. Assume that for each point $x\in X$ there
exists a divisor $D\in |E|$ in the complete linear system determined by $E$
whose complement $X\setminus D$ is a Stein neighbourhood of $x$ with the
density property. Then, the disc bundle $\Delta_h(E)=\{e\in E:|e|_h<1\}$ is an
Oka manifold while $E\setminus \overline{\Delta_h(E)}=\{e\in E:|e|_h>1\}$ is a
Kobayashi hyperbolic domain. In particular, the zero section of $E$ admits a
basis of Oka neighbourhoods $\{|e|_h<c\}$ with $c>0$. We show that this holds
if $X$ is a projective space, a complex Grassmannian, or a product of
Grassmannians. This phenomenon contributes to the heuristic principle that Oka
properties are related to metric positivity of complex manifolds.
