He partly replaced Conor Roberts, a rising star in the Labour Party who masterminded Mr Brown's 2010 election campaign and became chief political adviser before taking a job with Todd Property.
David Lewis, a longtime press secretary to Labour Prime Minister Helen Clark and a member of Mr Brown's 2010 inner circle, is on a retainer for three hours a week as a strategic political adviser. His position is under review with the arrival of Mr Lambert, who is taking on a more strategic role than that of Mr Roberts.
Mr Brown also has a part-time speech writer, Steven Armitage, and communications adviser Steve Boyd has been seconded to an alternative transport funding project.
Blogger David Farrar has questioned whether ratepayers are funding Mr Brown's re-election campaign.
In a post on his Kiwiblog site titled "Len's gaggle of spin doctors", Mr Farrar said Mr Brown's hiring of Dan Lambert took his tally of spin doctors to six - more than the entire parliamentary Labour Party.
Labour has five parliamentary press secretaries and a part-time speech writer for 34 MPs. Prime Minister John Key has four press secretaries and one media assistant.
Mr Brown refused to answer questions about communications staffing under his leadership.
Mr Lambert blocked repeated requests by the Herald to speak to the mayor, saying: "I think it's reasonable the mayor wouldn't want to go on record on a matter like this."
Orakei Local Board chairwoman Desley Simpson said Orakei ratepayers were funding the latest "propaganda manager" and the mayor's election campaign.
In the same posting, Mr Farrar challenged the right-wing Communities & Residents to select a mayoral candidate, otherwise Mr Brown and his spin doctors would have an easy time of it.
No one from C&R or the right has come forward to challenge Mr Brown for the local body elections, including Orakei councillor and the mayor's loudest opponent, Cameron Brewer.
Mr Brewer - a former "spin doctor" to Auckland City Mayor John Banks, Prime Minister Dame Jenny Shipley and Act leader Rodney Hide - said nobody would be able to match Mr Brown's army of spin doctors, advisers and consultants.