The Future Forward Party (FFP) has reaffirmed its intention to amend the 2017 constitution and restore faith in the parliamentary system.
FFP leader Thanathorn Juangroongruangkit said amending the constitution is a must-do and the main target will be the Senate's power.
Even though it is constitutional for the Senate to take part in choosing the prime minister, it is unfair and undemocratic, he said.
However, he admitted changing the charter would be an uphill task and that the party would need to mobilise public support as was the case with the 1997 charter.
He said the party will campaign to raise public awareness about controversial issues in the charter, but said he was not sure how long it would take before the charter amendment bid would gain momentum.
According to Mr Thanathorn, political instability can be expected after the general election due to the 2017 charter giving the Senate a role in choosing the prime minister.
He said if his party wins enough House seats to form a single-party government it will tackle two fronts simultaneously, which is to reduce the economic gap and restore faith in the parliamentary system.
"We must not allow the country to plunge back into the same cycle of coups and street protests which also have impacts on the economy.
"We have to restore people's faith in the parliamentary system, in the democratic system. It starts with political parties rejecting corruption," he said.
Mr Thanathorn said joining a coalition government will depend on talks and negotiations, but the party will not tolerate or support any attempted move that allows the regime to prolong its stay in power.
As an opposition party, the FFP will rely on checks-and-balances mechanisms in doing its job, but it is not against public demonstrations, which should be considered basic civil rights, he said.
"If there is injustice, we can't just ignore it. Public demonstrations aren't a bad thing but the previous street protests proved to have the hidden agenda of triggering the coup," he said.
According to Mr Thanathorn, the party is likely to win about 70 House seats in the March 24 election, but it could grab more seats with a good election campaign.
The FFP has nominated Mr Thanathorn as its only prime ministerial candidate.