He made the promise at Labor's annual state conference on Saturday, saying the move would put the interests of people in NSW first.
"Labor will deal directly with people, not through professional lobbyists," Mr Robertson said in Sydney's Town Hall.
Standing beside a large red banner with the message `Putting People First', the Labor leader said the measure would ensure government was not influenced by vested interests.
Under the proposal, Labor ministers, their staff and departments will no longer be allowed to meet third-party lobbyists, who advocate on behalf of the private sector.
Leadership reform
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Ordinary Labor members will also have a say in choosing the party's NSW leader in a reform aimed at taking away power from factional bosses.
The conference voted to support the plan which will come into effect after the March 2015 election.
Under the plan, leadership will be determined by a ballot weighted at 50 per cent caucus members and 50 per cent members of the party.
Public debates between candidates would also be held under the proposal.
State Labor general secretary Jamie Clements says it's the most significant reform undertaken by the party for more than 75 years.
Queensland Labor has already given its members a say in choosing its state leader after former prime minister Kevin Rudd brought in similar reforms at a federal level in 2013.
