Andy Burnham believes the contest is skewed by the backing of big unions Labour leadership candidate Andy Burnham is calling for a review of the leadership election rules.
Mr Burnham says the current contest is too heavily influenced by union funding and benefits the leadership favourites.
He also wants to change how a new leader is chosen, but insists he is not criticising his rivals and will support whoever wins under the current rules.
The final hustings of the leadership campaign is due to be held at the TUC in Manchester later.
Mr Burnham intends to set out plans for a shake-up after a new leader is chosen at the party conference later in September.
He believes the contest is skewed by the advantage given to those candidates who get the backing of the big unions – which guarantees them generous funding.
Mr Burnham is also critical of the high number of nominations required for a candidate to stand – currently 12% of the Parliamentary party or 33 MPs – which he believes acts as a barrier against less-favoured candidates.
He also believes MPs should not have their votes made public, arguing it encourages them to vote for who they think is going to win rather than who they actually want to back.
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