'In order to have a beneficial service, the person doing it must have some sort of religious rite and not be someone who smokes, goes back home to his wife and does things which aren't very moral.

'You can see if the person is really into it or is just playing around,' he said.

Association executive members are discussing how to deal with phoney monks.

Monks spend about three hours at each service and earn between $300 and $1,000 in a donation usually passed on via the funeral organisers in a lai see packet. Some monks recently complained of being undercut by their mainland counterparts and were criticised by the association as probable imposters.

But the Venerable Hin-hung said it was difficult to prove an improper ritual had been given.

'It's something that is really of another world so it would be difficult to [measure] such a thing.

'We just hope the 'consumer' can be a little more open as to who they're inviting,' he said.

'Don't trust people who hang around the death-bed and offer services.' An accountant at the Hong Kong Funeral Home in North Point, where funeral packages start from $10,000, said people were discouraged from bringing their own monks but some five services a day were done by independent monks.

'All the monks are professional in our funeral home, there are no strangers wandering around,' he said.

'For other homes, I don't know.'