Labour MP Louisa Wall has announced her resignation, 14 years after starting in Parliament. 

The list MP based in South Auckland won marriage equality for same-sex couples. 

Wall was first elected in 2008 on her party's list, and held the Manurewa seat from 2011 to 2020. 

But she was pressured not to run again in Manurewa at the last election. 

The Labour Party announced her resignation in a statement and Wall said she would not be speaking further today. 

Wall considered legal action against the party's ruling New Zealand Council for allowing one of her challengers, Arena Williams, to submit a late nomination. 

Wall today said events during the 2020 general election prompted her resignation. 

"It's been an honour to represent and provide a voice in parliament to those who are so often unheard," Wall said in the statement. 

"It was a privilege to lead the marriage equality law change," she added. 

"Not being able to get married to the person you loved unfairly marginalised members of the rainbow community and was unjust." 

She said she loved working as a parliamentarian and enjoyed building relationships with MPs from different parties. 

"Most recently I've thoroughly enjoyed my role as co-chair of the Inter-parliamentary Alliance on China and advocating for human rights." 

Wall said she'd keep involved with indigenous rights, human rights, equality and the rights of women and the LGBTQI+ community. 

She will make her farewell valedictory speech at Parliament on April 14. 

Prime Minister Jacinda Ardern said Wall was a hero to many throughout her parliamentary career. 

"Her commitment to human rights and equality has been absolutely unwavering. She has been relentless in her pursuit of human rights for all," Ardern said. 

The most likely person to replace Wall in Parliament is Lemauga Lydia Sosene, who is next on Labour's list. 

Sosene is currently chair of Auckland Council's Māngere-Ōtāhuhu Local Board. 

If Sosene chose not to go to Parliament, the next in line is former Army officer Dan Rosewarne from Waimakariri, Canterbury.