"We see Whanganui as a winnable seat for the Labour Party," Mr Kirton said.
Sitting MP Chester Borrows is not seeking re-election, meaning the electorate will have a new MP come September 23.
Two nominees have declared publicly their intention to seek the National Party nomination, district councillor Hadleigh Reid and Whanganui lawyer Harete Hipango.
National Party nominations close on March 1 and the successful candidate will be chosen on March 26.
Ms Baker-Hogan said she welcomed the contested nomination against Ms Lewis, noting Labour had not had a contested nomination for several years when Hamish McDouall, now Whanganui mayor, stood for Labour.
"I've congratulated Steph on her nomination and may the best woman win," Ms Baker-Hogan said.
She said if successfully elected as Whanganui MP she would resign as district councillor and would pay half of the cost of a by-election. She would remain on the health board if possible.
Ms Baker-Hogan has served as a councillor and health board member for over a decade, but said she has always had a strong interest in national politics.
She would go into bat for the provinces and wanted to address a "growing divide' between rich and poor, and between the provinces and main centres.
"I've been really disappointed how belatedly National have attended to the regions. It is time for change and a strong social agenda that addresses serious issues like the housing crisis, whilst ensuring economic growth assists all kiwis."
Ms Lewis said Whanganui was her hometown and that while she lived and worked in Wellington, she retained close ties to Whanganui.
Her father was a prison officer and also farmed in Waverley. She has sisters who attend school in Whanganui.
"In 2004 Jill Pettis selected me to be the Youth MP for Whanganui and I started a Young Labour Branch in Whanganui a few years ago," Ms Lewis said.
"I am looking forward to the upcoming debates and a friendly competition for selection. Whanganui is a winnable seat this election and I will be giving it my all."
Ms Lewis said she will be focusing on four key issues: jobs, education, health and housing.
"If selected as Labour's candidate I also intend to move back to Whanganui when the official campaign period starts."
