Labour's leadership contenders will be bound to a spending cap of $30,000 and will have to disclose all donations of more than $1500 toward their campaigns - but not until the campaign is over.
The donations rule is in a new code of conduct Labour has developed to ensure the US primaries-style contest is fair and clean.
The full code will be released today by the party and is expected to include expectations of good behaviour from candidates and their supporters.
The spending cap is slightly more than the $25,700 cap that applies to candidates in a general election, and the donation disclosure level is the same as for candidates under the Electoral Act.
Both Shane Jones and David Cunliffe have attracted backers in the past - in both the 2008 and 2011 elections Mr Jones declared just under $30,000 in donations, including $10,000 from Sealord in 2011 and $10,000 from Peter Talley in 2008, which Mr Jones said was due to their common Dalmatian ancestry.
Mr Cunliffe declared about $14,500 in 2011 and $9000 in 2008 while Grant Robertson declared no donations over the threshold in either election.
Yesterday, the three candidates answered caucus members' questions in a closed lunchtime session. Many MPs have already declared which way they will vote, but others say they are genuinely undecided.
The candidates will attend the first of 12 meetings with party members in Levin tomorrow before going to Auckland for two Sunday meetings.