A landmark piece of legislation intended to precipitate a global crackdown on corruption is in danger of losing all credibility because of a row over how it is monitored, warns Christian Aid.

Officials from more than 100 countries will gather in Doha, Qatar, next week to assess the effectiveness of the UN Convention against Corruption (UNCAC), which entered into force in 2005 and has been ratified by 141 countries.

Anti-corruption campaigners say a review mechanism is urgently needed to monitor how countries are implementing the Convention.

That mechanism, they say, must include the mandatory publication of country reports, country visits by experts from other states to check on progress, and the participation of civil society in the review process.

A similar system is already being used successfully to monitor the Anti-Bribery Convention drawn up by the Organisation for Economic Co-Operation and Development.

However, a vocal group of countries including China, Russia, Egypt and Pakistan are resistant, saying corruption is too complex and politically sensitive an issue to discuss openly. They are also concerned that civil society participation would be "adversarial".

Now a draft compromise to be put forward in Doha by the US, EU and a number of Latin American countries has been leaked.

Key proposals include allowing the country under review to insist "in exceptional circumstances" that monitoring reports into its activities should remain unpublished.

It would also be up to the country under review to provide those doing the monitoring with the views of civil society organisations from within its borders.

Christian Aid senior governance advisor Adele Poskitt, said it appeared that a secret deal involving the EU and US was already in place".

"One which would ensure that there is no effective mechanism to hold governments to account for implementing the Convention," she said.

"Corruption is a major threat to development, exacerbating and sustaining poverty. An effective review mechanism would be fully transparent, with civil society at its heart, ensuring that even the most recalcitrant and oppressive of signatories faces at least some pressure to change their ways.

"The compromise on the table casts a doubt on the ability of the international community to tackle corruption and the political will of world leaders to make it happen.

"If a weak review mechanism is agreed next week it will give a message to corrupt individuals and groups that their activities will go unpunished."

Ms Poskitt said the secret deal that had been arrived at appeared to fly in the face of calls just a month ago by the G20 in Pittsburgh for the enforcement of laws against transnational bribery and an "effective, transparent, and inclusive mechanism for the review of the Convention".

It also runs contrary to assurances by G8 leaders in July this year that they were committed to "ensuring effective implementation of the Convention against Corruption", said Ms Poskitt.

The chief executives of nearly 100 major concerns, including General Electric, Royal Dutch Shell Group, BP and Anglo American plc recently wrote to the UN Secretary-General Ban Ki-moon asking him to use his influence to ensure an adequate review mechanism was agreed.

They warned that the Convention’s success "will remain uncertain until an effective implementation review mechanism is established". They added that further delay "would damage the credibility of the Convention and its ability to build momentum in overcoming corruption".

Faith leaders have also added their voices to demands that wrangling should end. More than 100 Christian, Islamic and Jewish leaders from around the world have written to the UN Secretary-General calling for a review mechanism to be introduced as part of the "moral imperative" of tackling corruption.

The faith leaders’ letter said: "Two elements essential for a robust and credible review mechanism are transparency and the participation of civil society.

"Transparency – via the publication of reports and recommendations – is vital to ensure a fair and effective process. Honesty and integrity are the moral values that underpin any attempts to tackle corrupt practices and a commitment to a transparent review mechanism is testimony to political leadership that is mature and accountable.

"Civil society can positively contribute to the implementation of the Convention and the review process. Civil society organisations, including faith groups, provide an important link to communities experiencing poverty.

"The review mechanism must make room for the voices of men and women living in poverty. Indeed, if those most affected by corruption are not accorded space to feed in to the review, it will be impossible to accurately measure UNCAC’s effectiveness."