When former German chancellor, Gerhard Schröder, joined the supervisory board of pipeline consortium Nordstream in March 2006, it raised a few eyebrows - and not just because Russia's state-owned Gazprom is involved in the project.

Schröder had been Germany's chancellor until November 2005, so his transition from politics to business was quick to say the least.

Under a new bill passed by the cabinet on Wednesday, former ministers and deputy ministers will have to observe a cooling-off period of 12 months before taking up a post with a company or other private enterprise.

If the government sees a conflict of interest, or a danger to the public, it can impose a cooling-off period of up to 18 months.

"It's a step in the right direction, as we didn't have any regulation before. In theory, you could switch from one day to the next," Wolfgang Jäckle from Transparency International Germany told DW. The rules are designed to prevent politicians' decisions being influenced while still in office.

"If a company is likely to offer a minister or deputy minister a job, there is the danger that the decisions he makes, possibly without being aware of it, while still in office, are affected by that," Jäckle told DW.

"But I fear its impact will be limited, as the cooling-off period that's been set is too short." Both Transparency International and Lobby Control, are demanding a period of up to three years. Germany's opposition Green party also prefers a three-year period.

The ruling Christian Democrats have defended the bill, with Interior Minister Thomas de Maiziere arguing that the bill involves a "limit on what jobs ministers can do, it's affecting basic rights, and that's why we have to treat this carefully."

'Revolving door' alive and well

There have been several high-profile cases in Germany in recent years passing through what's often referred to as the "revolving door" between politics and business. Former development minister Dirk Niebel, for example, joined the arms group Rheinmetall in January, just over a year after resigning from politics, where he was a member of a parliamentary committee tasked with regulating weapons exports.

The former head of the chancellery, Ronald Pofalla, took up a lucrative post at Deutsche Bahn, and former health minister Daniel Bahr joined Allianz's private health insurance arm less than a year after quitting his post.

Under the new bill, which still has to be approved by both houses of parliament, an ethics commission made up of three people "from the public sphere" is meant to assess if there is a conflict of interest and issue a recommendation, but Jäckle says it is not clear who exactly will be on the committee and how they will arrive at their decision. Plus, the government will have the last say anyway.

US, UK regulations

In the US, former lawmakers need to wait two years before registering as a lobbyist, but there is no such restriction on taking up a post on a corporate board.

Sixty percent of US lawmakers joined a company board within a year of quitting their position as a senator or governor, according to recent research by Professor Maxwell Palmer from Boston University and Benjamin Scheer from Harvard University.

Service on a company board can also often occur inbetween political posts. Former US Secretary of Defense, Chuck Hagel, for example, spent three years on the board of oil giant Chevron between resigning from the Senate and becoming defense minister.

In the UK, former ministers and senior civil servants- but not other members of parliament - must apply for advice with the Advisory Committee on Business Appointments (ACOBA), which is tasked with assessing the suitability of the new post.

The committee can impose waiting periods, but it is only an advisory body that cannot issue sanctions and whose advice has been ignored in the past. Transparency International UK is therefore demanding an overhaul of the rules.

In soon-to-be published research, it calls for ACOBA to "be replaced with a new statutory body with sufficient resources and powers to regulate the post-public employment of former ministers and crown servants and sanction misconduct."