More than a quarter of people living in Asia had to pay a bribe while trying to access a public service in the past year, a watchdog said Tuesday, calling on governments to root out endemic graft in the region.

The report by Berlin-based Transparency International (TI) surveyed more than 20,000 people in 16 countries spanning the Asia Pacific region from Pakistan to Australia.

From the results they estimated 900 million people were forced to fork over “tea money” at least once in the previous 12 months.

Bribery rates were highest in India and Vietnam, where nearly two thirds of respondents said they had to sweeten the deal to access basic services like public education and healthcare.

Japan, South Korea, Hong Kong and Australia reported the lowest incidences of bribery.

Police were the most common demanders of kickbacks, according to the survey, with just under a third of people who had come into contact with an officer in the past year saying they had paid a bribe.

The poor are hit hardest by corruption with 38 per cent of respondents saying they had to pay a bribe, the highest in any income category.

Yet while poorer people were more likely to be targeted in countries like Thailand, India and Pakistan, the reverse trend was found in places like Vietnam, Myanmar and Cambodia.

“Governments must do more to deliver on their anti-corruption commitments,” Jose Ugaz, the chair of TI, said in a press release.

“Bribery is not a small crime, it takes food off the table, it prevents education, it impedes proper healthcare and ultimately it can kill.”

When it came to perceptions of corruption Malaysia and Vietnam got the worst ratings from their citizens, who felt graft was widespread and accused their governments of doing little to fight it.

Corruption scandals have rocked a number of governments in Asia over the past year, dominating news headlines and whipping up protests.

South Korea's President Park Geun-hye was impeached by parliament in December over a major influence-peddling scandal that prompted millions to take to the street for months to call for her resignation.

Malaysia has also been seized by a graft scandal since 2015, with global investigators accusing Premier Najib Razak and his associates of misappropriating billions of dollars through the state-backed 1MDB fund.

A report last year by a corruption watchdog also detailed the enormous wealth accumulated by the family and friends of Cambodian Prime Minister Hun Sen.

China, meanwhile, has been on anti-corruption drive that has netted more than one million officials, while fellow communist country Vietnam has also jailed a number of former businessmen for graft in its bloated state-run sector.

Thailand's junta government has vowed a similar anti-corruption campaign but there have been few convictions so far.