A committee, headed by Palad Nivit, which was investigating allegations that many foreign-run diving companies on the island were evading tax, drew up the proposals.

Palad Nivit said if the proposal was approved, dive companies would have to register at the marine office within 30 days.

The operators must provide documentation and apply for a permit to operate, to be issued by the governor.

"Dive operators will have to declare all information about their business, such as the number of boats, how many trips they make a day, how payment is received, the number of employees and whether foreign employees have work permits," he said.

Phuket Marine Office chief Surin Theerakulpisut said: "Dive operators will have to show us information about their businesses, including telling us about their websites.

"They will have to show us all their accounts so we know how much revenue they receive so we can calculate tax demands."

Surin said the Phuket dive industry was believed to generate about Bt3 billion a month.

"The province has never received full tax income, but these rules will help us collect revenue in full," he said.

Several points remain unclear, including what information will be required, what penalties will be imposed for non-compliance and how long it will take for permits to be issued.