Mr Pohiva, who died in September, had held the Tongatapu No1 seat for 32 years.
The by-election will be held on 28 November.
Noted scientist Netatua Prescott Taufatofua is competing against Mr Pohiva's eldest son, Saiosi for the seat.
She said there was a lot of talk of good governance and accountability but those principles were not always respected by members of parliament.
Ms Taufatofua said that it was critical that aid development spending rules were followed.
"So that it is fair to people who are bidding, fair in distributing the benefits of those development projects, they are reaching those that they are supposed to reach, the outcomes are achieved in time, I would change some of the legislation."
Meanwhile, Saiosi Pohiva said he wanted to continue his father's campaign to make the country fully democratic.
He said he knew his father had left big shoes to fill and he would continue to try to bring more democracy to Tonga.
Mr Pohiva said more democratic reforms were needed to usher in good governance and equal opportunity.
"Unless the system is reformed we will struggle. I am looking at something sustainable that can only be done through good governance. We can give food to the people, but how long would that last. We can provide things for the people but that's not sustainable.
"We are looking to empower the people through good governance."