Civil service chiefs across Whitehall have been sent new guidance on ministerial conduct following a "damning" report into the Liam Fox scandal, MPs were told.
David Cameron has accepted recommendations to tighten up procedures contained in the report on the former defence secretary by Cabinet Secretary Sir Gus O'Donnell.
Commons Leader Sir George Young said the Cabinet Secretary was writing to permanent secretaries, the senior departmental civil servants, to "set out the processes that now need to be followed".
The report from Sir Gus found Dr Fox, who resigned last week, had been in breach of the ministerial code of conduct as a result of his links with friend Adam Werritty, who presented himself as an adviser to the then defence secretary.
Sir George updated MPs on Sir Gus' report, despite Labour's calls for David Cameron to deliver the statement.
The Commons Leader said: "At the end of the last parliament, public trust in Parliament was at an unprecedented low.
"This Government is committed to working to rebuild confidence in our political and democratic institutions and we will continue to put in place any measure necessary to ensure that the highest standards, rightly expected of our elected representatives, are met."
The Government was committed to a statutory register of lobbyists, with a consultation document due out next month, Sir George added.
Shadow Commons leader Angela Eagle said Dr Fox had treated the ministerial code as an "optional extra".
She said the inquiry by Sir Gus, though "damning", was limited in scope and "merely scratches the surface of potential misconduct in Government".