It comes as the Commons standards committee prepares to publish its review of the code for MPs.
Labour is calling for an overhaul of the system regulating ministers’ conduct – accusing PM Boris Johnson of failing to enforce the current rules.
Deputy leader Angela Rayner will say ministers should be banned from work relating to their past job for five years after leaving government.
It comes as the Commons standards committee is due to publish its own review of the MPs’ code of conduct.
The government has said it is committed to “reinforcing high standards”.
There has been renewed scrutiny of standards in general at Westminster recently – after the government’s failed attempt to change the system while blocking the suspension of the former Conservative MP Owen Paterson.
Labour argues current system of rules on ministers’ behaviour do not work and have failed to prevent what it describes as government corruption.
In a speech on Monday, the party’s deputy leader Angela Rayner is expected to say democracy “cannot hinge on gentleman’s agreements” and will call for a new body to replace the current post of independent adviser on ministerial interests.
Ms Rayner will argue that the role is “toothless” because it cannot investigate possible breaches of the rules by ministers unless ordered by the prime minister.
Instead, Labour says it would set up an “independent integrity and ethics commission” that could initiate investigations into ministers’ conduct without having to first seek the approval of the prime minister.
The commission would also be able to punishments when misconduct has been proven.
And a key new rule would see former ministers banned from accepting jobs linked to their past ministerial roles for at least five years after they leave office, the party says.
Later on Monday, the Commons standards committee, chaired by Labour’s Chris Bryant, will publish its review into the current code of conduct for MPs.
A Cabinet Office spokesman said: “The government has committed to continually reinforcing high standards of conduct in public life so the public can have trust and confidence in the operation of government at all levels.
“It’s absolutely right that we fully take account of all of the evidence and work up the best solutions before responding.”
The spokesman said the government would consider past reports – including one by the Committee on Standards – and would give an update to Parliament “in due course”.