A Labour assembly member has urged his party to ensure it ends the "lottery" of the assembly's electoral system.
Too many candidates win the election 'lottery', it is claimed
Rhondda AM Leighton Andrews said Labour should "stop losers becoming winners" under regional list voting.
Labour holds a conference at the weekend on the Richard report, which recommends changing its polling system.
Opposition AMs have hit back over the system which was brought in by Labour - and have accused the party of seeking "a one-party state in Wales".
Mr Andrews ridiculed AMs who were able to stand in both constituency seats and on the regional list as "neutered, smashed and stuffed".
He was speaking ahead of Saturday's special Labour conference in Cardiff at which party members will vote on the Labour proposals on the assembly's future.
It follows consultation of Labour members by the party and a recommendation by a commission chaired by Lord Richard that the assembly should gain primary law-making powers.
But other issues under the spotlight include the voting system. Welsh Secretary Peter Hain has already promised to overhaul the "ridiculous farce" which allows candidates to win a seat via the list system under proportional representation even though they have lost in a constituency under the traditional first-past-the-post system.
Mr Andrews - who won 61% of the vote in his constituency at the 2003 election - used the lotto as a metaphor for his message and said: "The only lucky winners revealed on election night should be the voting public.
"And if they reject someone at the ballot box, they do not expect that candidate's bonus ball to come up later that night as they sneak in on a list.
Leighton Andrews says the list system is a "bonus ball" for candidates
He added: "Ninety per cent of the 20 assembly list members were defeated in constituency contests but then got elected on the regional lists.
"All three defeated candidates in Clwyd West joined Labour's victorious Alun Pugh in the assembly by being elected on the north Wales regional list."
He described assembly Tory group leader Nick Bourne as "battered in Brecon," Plaid Cymru's Janet Davies as "obliterated in Ogmore," and Lib Dem Peter Black as "stuffed in Swansea East".
Mr Black responded: "If Leighton wants to exercise his limited vocabulary, that's up to him.
"Labour should be looking at a voting system that is fair and equitable - they are just trying to alter a discredited system to get a Labour majority."
Plaid Cymru's Dai Lloyd (described by Mr Andrews as "smashed in Swansea") said: "I don't like the present system, but it was Labour's idea. Obviously, it is too successful.
"We haven't been able to sort out a one-party state in Wales yet, which is why they want to change it.
"We have always been for a single transferable vote system.
"If Labour thought about it, they would be the biggest winners with an STV system."
Tory AM William Graham said: "We would not favour restrictions on standing in elections.
"I doubt this will win Leighton a promotion in Rhodri Morgan's next cabinet reshuffle."