Stormont special advisers must be subject to Civil Service discipline - and have their salaries cut - the Ulster Unionists insist.
And Assembly committees should be given real teeth to hold Executive Ministers to account, the party says.
The demands are part of a UUP five-point plan to "clean up" Stormont.
Leader Mike Nesbitt said the DUP and Sinn Fein Executive had dragged the reputation of the Assembly "from the gutter to the sewer".
In the party's first major election event, Mr Nesbitt also referred to former First Minister Peter Robinson, who he said had "famously boasted the greatest achievement of the 2007-2011 mandate was that it survived. They cannot even manage that anymore".
Mr Nesbitt, who along with the SDLP and Alliance, quit the Executive after last May's election to form an Opposition, argued his proposals could help restore public confidence "in the integrity of devolution".
Special advisers (Spads) have been at the centre of ongoing revelations around the botched Renewable Heat Incentive (RHI) scheme.
However, they were also involved in earlier Stormont controversies, including the Red Sky affair, when former Spad Stephen Brimstone was in the spotlight.
Despite criticism from an Assembly committee that Mr Brimstone had been "deliberately evasive", he was later promoted from the then Department for Social Development to the Office of the First Minister and Deputy First Minister.
Mr Nesbitt said: "It is time that special advisers became subject to the Northern Ireland Civil Service disciplinary process to ensure public confidence in their accountability.
"We must also end the situation where some special advisers are paid more than an Executive minister.
"In the new mandate their salaries must be capped.
"The past number of years have seen the Executive embroiled in many scandals including Red Sky, Nama and RHI. These have raised allegations around the actions of ministers and their special advisers.
"If any of these allegations were to be substantiated, it is vital that the PSNI has the will and required resource base to deal with any referrals."
He said, as things stand, ministers who are alleged to have broken the ministerial code need not face investigation.
"An MLA can have their conduct investigated by the Assembly Commissioner for Standards, yet there is no such process for ministers," he said.
"It cannot continue to be the case that there is a greater level of accountability placed on MLAs than on those being trusted with the public purse."
The UUP further said the office of Speaker had been brought into disrepute after the DUP's Robin Newton allowed former First Minister Arlene Foster to make a speech on the RHI scandal, even though Deputy First Minister Martin McGuinness had withdrawn his permission.
Mr Nesbitt said: "The election of the Speaker can no longer be subject to a carve-up between the two largest parties. We want to see future Speakers elected through a secret ballot of MLAs."
He added: "Ministers must be effectively scrutinised. That role should be performed by the Assembly's statutory committees, yet their legal duty is to 'advise and assist' ministers, not scrutinise them.
"We want to strengthen the role of Assembly committees, making effective, detailed scrutiny a statutory duty.
"The last 10 years of an Executive led by the DUP and Sinn Fein have been characterised by a descending spiral of incompetence, arrogance and the whiff of cronyism and corruption.
"Nothing will change unless the public vote for it."