[4] Following the formation of a Labour-led coalition government on 19 October 2019, Marcroft was designated as New Zealand First's spokesperson on the Accident Compensation Corporation (ACC), arts, culture and heritage, broadcasting, communication IT, conservation, environment, health and human rights.

[5] On 23 October 2019, Marcroft successfully secured an amendment into David Seymour's End of Life Choice Bill that the Government hold a binding referendum on decriminalising euthanasia.

In justifying her call for a referendum on euthanasia, Marcroft stated that "this issue basically, directly affects the fabric of society and so we believe that temporarily empowered politicians … we alone should not decide on the bill."

[8] She and her fellow NZ First MPs also lost their seats after the party's vote dropped to 2.6%, below the five percent threshold needed to enter Parliament.

[16] At New Zealand First's campaign launch for the 2023 general election Marcroft announced the party's proposal to reform Pharmac and increase the medicines budget by 1.3 billion dollars.

[17] On 16 September 2023 Marcroft was ranked fifth place on New Zealand First's party list and stood in the Kaipara ki Mahurangi electorate.