The undercover investigations have thrust the issue of lobbying into the limelight and had already forced a member of the lower house of parliament, Patrick Mercer, to resign from the ruling Conservative Party and seek legal advice.
The three House of Lords peers caught out by a Sunday Times sting operation are John Cunningham and Brian Mackenzie of the main opposition Labour Party and John Laird of the Ulster Unionist Party.
All three denied breaking the chamber's rules but their parties took swift action against them.
"Lord Cunningham and Lord Mackenzie of Framwellgate have been suspended from the Labour Party pending further investigation," the party said in a statement.
Mike Nesbitt, leader of the Ulster Unionists, said in a statement he had called Laird after reviewing the media coverage and as a result of that call Laird had resigned from the party pending an investigation.
The trio were covertly filmed offering to ask parliamentary questions, lobby ministers and host events in prestigious House of Lords premises in exchange for payment by what they were told were lobbyists acting for companies.
The scandal will renew pressure on Prime Minister David Cameron to introduce a statutory register of lobbyists, as promised in 2010 in the coalition agreement between his Conservatives and their junior partners, the Liberal Democrats.
Cameron warned more than three years ago that lobbying was "the next big scandal waiting to happen" but critics, including some Liberal Democrats, accuse him of dragging his feet.