It is possible to create a nether portal with a minimum width of 2 and height of 3. However, a rotation of these dimensions will not retain the validity of the portal; a 3+-wide, 2-high portal cannot be lit.
MC-135871
Rotational inconsistency with possible nether portal sizes
Resolved
Works As Intended
0
This is WAI, nether portals need to have a minimum height of 3 and a width of 2. This would be a feature request.