The survey, carried out by Populus for PRWeek, reveals that 58 per cent of 132 MPs quizzed on the matter think a lobbying register should include both in-house and third party lobbyists.
The findings conflict with government moves to introduce a register that would exclude those in-house, and come after ongoing and widespread condemnation of the proposals by the PR industry.
Of those polled, 23 per cent strongly supported including in-house lobbyists, compared with two per cent who strongly opposed it.
Populus’ findings show that 76 per cent of Labour MPs backed the inclusion of in-house lobbyists, compared with 59 per cent of Liberal Democrats and 36 per cent of Conservatives.
PRCA director of comms Matt Cartmell said: "This proves there’s an appetite for the universal register, something we’ve called for all along, among politicians too. Why the Government isn’t listening to us, I don’t know – it’s about time it did."
The lobbying register is passing through Parliament as part one of the wider Transparency of Lobbying, Non-Party Campaigning and Trade Union Administration Bill, which has also been attacked for part two, which covers charity funding.
Last month the Cabinet Office quashed hopes that a pause in the progress of the bill through the House of Lords to further scrutinise the charity proposals could lead to a rethink on the lobbying register.
With initial scrutiny concluded in the House of Lords this week following approval by the House of Commons, a report stage is set to follow in the New Year.
CIPR director of policy and comms Phil Morgan said: "MPs now seem to agree with what the industry has been saying. There are still more amendments that can be brought forward, and it would be good to think this polling could influence government thinking."
The credibility of the proposals also received a blow in terms of which parliamentary figures would be covered.
Forty-nine per cent backed a register that covered lobbyist contact with not just ministers and permanent secretaries as is currently proposed, but special advisers and MPs too.
This compares with 38 per cent who opposed the idea.
Overall, only 23 per cent supported the option of doing nothing in relation to regulating lobbying, but among Conservative MPs 43 per cent backed the idea.
The Cabinet Office had not responded to a request for comment at the time of publishing.