It is also one of eight constituencies in the South Wales Central electoral region that elects four additional members (along with eight constituency members), to produce a degree of proportional representation for the region as a whole.

In general elections for the Senedd, each voter has two votes.

The first vote may be used to vote for a candidate to become the Member of the Senedd for the voter's constituency, elected by the first past the post system.

Additional member seats are allocated from the lists by the d'Hondt method, with constituency results being taken into account in the allocation.

Regional ballots rejected at the count: 147[7] 2003 Electorate: 63,204 Regional ballots rejected: Not reported[10]