With the final vote count released on Friday, Lewis finished with 54.3 per cent of the candidate vote (22,299) with an 8191-majority over National's Harete Hipango.
"I don't think you could print what I said when the final result came in. Of all the seats that flipped from National to Labour, Whanganui now has the biggest majority."
Lewis said she would also begin to prepare her maiden speech to Parliament which could happen sometime in December.
"We're all getting sworn in on November 25, and then there'll be a Speech from the Throne from the Governor-General on the November 26. After that, Parliament will resume normal business.
"Part of that business is getting 40 odd new MPs through their maiden speeches, so mine could be in early December."
A third of Labour's caucus was made up of new MPs, Lewis said, which was a "real rejuvenation".
"If you look at the diversity, from different cultures, backgrounds, ethnicities, and from across the country, It truly feels like a cross-section of the New Zealand public.
"There are different ages as well, and I'm not going to lie, it's good to see a little less grey hair in there.
"Something I've said right throughout both my campaigns is that people down in Parliament are making decisions that are going to affect my generation and now my daughter's generation for years and years to come."
"I have a very long list of issues from constituents I've been talking to right across the electorate who have asked me to raise their concerns or questions when the time comes in the caucus, and I will absolutely do that."
