Greater transparency surrounding political lobbying in the UK is needed, the chair of an anti-corruption watchdog has warned, ahead of an expected recommendation that ministers should be banned from lobbying for up to five years after leaving office.

In an interview with the BBC, Lord Jonathan Evans, the head of the committee on standards in public life, said there was “nothing wrong with lobbying in principle”. But he stressed there needed to be a “level playing field”, with detailed information on the nature of lobbying regularly provided to the public and stricter rules governing actions of former ministers.

On Monday, the committee, an independent body that advises the prime minister on ethical standards, will publish the findings of its emergency review, prompted by the Greensill scandal earlier this year, during which former prime minister David Cameron repeatedly lobbied cabinet ministers and senior officials on behalf of Greensill Capital, the collapsed supply chain finance company where he was employed as an adviser.

The Sunday Times newspaper has reported that the report will make a series of recommendations including banning ministers from lobbying for up to five years after stepping down.

It also said the report will also propose introducing anti-lobbying clauses into the employment contracts of government officials such as special advisers and will urge the government to publish details of lobbying meetings every four weeks instead of quarterly.

Speaking to the BBC’s Westminster Hour programme on Sunday ahead of the report’s publication, Evans said that information about lobbying ought to be published more regularly by government departments, to provide clear information on which ministers had been lobbied and the detail of topics discussed within meetings.

“In theory, the information about lobbying should be published regularly by government departments so that people can check and see who’s been lobbying which minister. That hasn’t been happening as frequently as it should in our view,” he said.

“We need to have details about what was discussed. Just saying ‘a meeting to discuss Brexit’ or whatever, that doesn’t tell you anything.”

The former head of M15 also warned that “current arrangements” in regard to former ministers lobbying do not “command public confidence”, adding: “Where a minister has had specific policy responsibility, there may well be cases where it’s proportionate and right that they should wait a little bit longer than two years.”

Evans emphasised the importance of investigating lobbying concerns in a vigorous manner, arguing that leaving matters unresolved risked becoming “politically damaging” and undermining public trust.

Evans told the BBC that he was “surprised” at the extent of lobbying surrounding Greensill, particularly by text message, adding: “It didn’t look to me to be appropriate that that level of intervention should be going on without it having been properly declared.”