"I want to set a precedent to show that I am serious and I am happy to put some skin in the game," he said.
"Yes, I am looking to advocate for people within a higher level of government, but that does not mean I am not serious about my community and saving them some of the cost of finding a replacement."
But the move has come under fire from ousted councillors David Stewart and Wayne Moultrie, who described it as "opportunistic", claiming Cr Morris had used "local government as a stepping stone".
Mr Stewart said: "I believe if you have the vote of the people, then you should honour that.
"This comes across as opportunistic and is very disappointing for the ward he represents."
But Cr Morris said he had not used the council as a stepping stone.
He said had heard the news of Mr Ryall's retirement just days before the formal announcement was made in February, months after the local government election.
"I have been a National Party member for 10 years and worked on Mr Ryall's election campaign. However, the news was a complete shock, he said.
"I thought he would stay put for at least five more years, because he has done such a tremendous job."
Cr Morris said the decision to put his name forward "did not come easily" and it was not "selfish ambition" that drove him.
"The new council is working well as a team and we are finally bringing the cost savings to the city that everybody has been waiting for," he said.
"In the last six months alone I have been part of a team that has saved ratepayers $34 million and shaved $14 million off budgeted debt, so this has been a tough decision to make."
Cr Morris said he believed it was important the next Bay of Plenty MP was a local, someone with "a stake in the ground" who would stay in the community even if they were not successful.
Not taking the opportunity could mean putting his political ambitions on hold for 15 years or more.
"This kind of opportunity might not come up again for 15 years or more if we did select someone else," he said.
"I would be in my mid-40s by then and it would be difficult entering Parliament as a backbencher then. Going for it now means I can do my time as a backbencher, advocate for my community at a higher level and still be young enough to perhaps become a minister in the future.
Cr Morris said he would continue his work as a councillor as he campaigned.
"I am a person who can run off little sleep and I am prepared to give 110 per cent to both.
"I am used to campaigning and I am willing to put my blood, sweat and tears into this."
Cr Morris said legally he could keep his council role and take on the MP position but he would not do that.
"You would not have enough hours in the week to do that," he said.
Tauranga Mayor Stuart Crosby welcomed the news, saying it was part of the "democratic process".
"I have no issue at all with Steve having a crack at this," he said.
"I know it's been a long-term goal of his to get to Parliament and sometimes you have to take opportunities when they arise."
National Party Bay of Plenty electorate chair Mark Bayly said he was unable to comment on the number of people interested, with nominations opening for pre-selection on April 19.
"I can say there has been a lot of interest from several parties but, aside from Mr Morris and Mr Muller, the rest are keeping quiet for now."
The candidates will be whittled down to five by Bay National Party members, with a final announcement expected in early June.
Mr Ryall and Labour candidate for Tauranga Rachel Jones could not be contacted in time for this edition.
