New South Wales Opposition Leader John Robertson. (AAP)  John Robertson has stepped down as NSW opposition leader following revelations he signed a letter on behalf of Sydney siege gunman Man Haron Monis in 2011.  The shock resignation comes three months ahead of the NSW election in March, which is expected to be won easily by the Mike Baird-led coalition government.  Deputy leader Linda Burney will become acting NSW Labor leader ahead of a caucus ballot to elect a permanent replacement on January 5.  Mr Robertson said he had lost the confidence of senior colleagues.  "Labor must be united behind the leader," he said on Tuesday.  "And so, as a lifelong Labor man, I have chosen to step aside as Labor leader."  Mr Robertson, who took the helm in March 2011 following one of the worst electoral routs in the state's history, came under pressure on Monday when he disclosed having helped Monis with a request in August 2011.  Monis had approached Mr Robertson's electoral office seeking help contacting the Department of Family and Community Services in relation to a family dispute.  Mr Robertson signed and forwarded a letter to the department on Monis' behalf, noting that he was subject to an AVO and ongoing family court proceedings.  The department later rejected Monis' request, but news of the letter has tarnished Mr Robertson's image.  He has maintained that the letter did not support or endorse Mr Monis, who had earlier been censured for sending inflammatory letters to the families of Australian soldiers killed in Afghanistan.  He said he designed his office to help anyone in the Blacktown community.  "Even if I wasn't willing to advocate or support their cause, I would at least facilitate them in putting their request to the appropriate government agency," he said.  But he accepted that his actions appeared questionable in the wake of last week's Lindt Cafe siege, which ended with the deaths of Katrina Dawson and Tori Johnson. The pair were farewelled at separate services in Sydney on Tuesday.  "My heart goes out to the victims and their families, especially today," Mr Robertson said.  "I offer my sincere condolences and they should know that we all are grieving with them."  Mr Robertson said he was disappointed that after four years he was not going to lead Labor to the 2015 poll.  But he said he was proud of his role in clamping down on corruption in the NSW party branch.  "I have rid the party of those who betrayed the great Labor cause," he said.  "We have dragged the party out of the pit of electoral oblivion."  Do you have any news photos or videos?
There could be a push for NSW Opposition Leader John Robertson to resign following revelations he helped a request from the Sydney siege gunman.