Labour's only Chinese MP, Raymond Huo, could be out of Parliament if the party wins the Christchurch Central seat.
The Labour and National candidates there are tied on 10,493 votes, and the final winner will not be known for two weeks after about 3000 special votes are counted.
Mr Huo said yesterday that a victory there for Labour's Brendon Burns might be at his expense if the special votes did not also boost party vote numbers for Labour.
"We have been left very disappointed with the results, because we have tried and worked really hard to win the ethnic vote," said Mr Huo, a former journalist and lawyer who was Labour's first Chinese MP in 2008.
Labour's diversity in Parliament has already been diluted, with Maori MP Kelvin Davis and the party's first MP of Tongan descent, Carmel Sepuloni, missing out because of the dismal showing at the polls.
Mr Huo said Labour would be going back to the drawing board to see where it went wrong with the ethnic vote, and that the party was "committed to connect with them in time for the next election".
"But it is critical that [we] continue to have diverse ethnic representation in Parliament."
Should Mr Huo not make it back to Parliament, Labour will be left with just Indo-Fijian Rajen Prasad as its sole Asian MP.
Diversity in Parliament hit a historical high after the 2008 election when MPs from communities never before represented entered through their respective party lists.
But National was left without a Chinese MP for nearly a year after former Ethnic Affairs Minister Pansy Wong resigned in January, and Labour has lost its only Muslim MP, Pakistani-born Ashraf Choudhary, who decided not to stand.
However, the surprise return of New Zealand First and the surge in popularity for the Greens have helped to maintain the number of Maori MPs and pushed up Pacific Island MPs.
NZ First's Asenati Taylor, a Samoan, will boost the number of MPs of Pacific Island descent to five, up from four in the last election.
University of Auckland's Jian Yang enters Parliament off National's list, and will become the party's new Chinese MP to replace Pansy Wong.
National's Korean-born Melissa Lee and Sikh-Indian Kanwaljit Singh Bakshi are also returned on the list, despite a poor showing in their respective electorates of Mt Albert and Manukau East.
Unlike last time, there was no "Chinese battleground" at Botany. The New Citizens Party, a Chinese-backed party, withdrew from the election.
In Botany, where immigrant voters outnumber the locals, National incumbent Jami-Lee Ross cruised home with 16,302 votes - and a 10,054 majority.
Labour's Taiwanese-born candidate, Chao-Fu Wu, managed 6200 votes and the Conservatives' Paul Young 2000. The Conservatives had put Asian candidates high on the party list - with little reward.
Fewer women will also be MPs this time, with just 38 - or 31 per cent of Parliament. After the 2008 election there were 42 women, making up 34 per cent.By Lincoln Tan Email Lincoln