Robson was heavily involved in the establishment of Anderton's NewLabour Party (NLP), which later became the core of the Alliance.
[3] In December 1992, following the Wellington Central by-election, Robson was designated NLP spokesperson for defence to replace Keith Locke whom Anderton considered too left-wing.
However, Anderton easily held onto his seat, allowing Robson (standing in Manukau East, where he came fifth), as the 2nd-ranked person on the Progressive list, to return to Parliament.
Robson has a relatively high public profile, compared to the size of his party, and is known for his views on foreign affairs and justice.
Along with the Green Party's Keith Locke, Robson campaigned on behalf of detained asylum-seeker Ahmed Zaoui.
In 2002, Robson introduced a Private Member's bill providing for four weeks of paid annual leave for all workers, a proposal that the Labour Party initially opposed.
Robson's legislation, however, ultimately forced Labour to either vote in favour of the bill or risk alienating its trade union supporters, who vociferously advocated it.
[10] On 14 July 2022, Robson had the rare distinction of appearing twice, in positions 47 and 72, in the list of politicians, academics, activists promoting Russian propaganda published by the Ukraine Government.