Science and Technology Minister, Batty Weerakoon, said that he passed on the contents of the e-mail message to the state-run media.

Ranil Wickremesinghe tells how he found out about the intercept

Opposition leader Ranil Wickremesinghe, a former prime minister, said the minister had read it out at a cabinet meeting last week.

"This is a very serious matter," he said after raising the issue in parliament.

He said that he discovered his e-mail had been intercepted when he read about it in a local newspaper.

He said that the incident was typical of the government's strategy of "stealing" electronic correspondence of politicians, journalists and private businessmen.

The opposition United National Party of Sri Lanka says that the tapping of telephone and fax messages has been going on for some time.

The BBC's Amal Jayasinghe in Colombo says the party feels that the present government is only maintaining a time-honoured tradition of spying on political opponents.

But the opposition says that the tapping of the personal e-mails of Mr Wickremasinghe is taking things too far.

Mr Weerakoon told parliament he believed a computer server had accidentally sent him the opposition leader's e-mail.

Irony

The message was from the British marketing and advertising company, Saatchi and Saatchi, and contained details of election campaign strategy.

The opposition says the minister has clearly violated the law by stealing the message and by releasing its contents to the state-run media.

This is something of an irony for Mr Wickremesinghe, because it was he who negotiated with the United States to ensure that Sri Lanka gained access to international information superhighway when he was prime minister between 1993 and 1994.

The opposition leader says he is concerned that spying now extends to private businesses instead of politicians and journalists who he says were targeted in the past.

"They first started to check the reports filed by foreign correspondents," the former prime minister said. "Now they have expanded it to cover businessmen."

The opposition leader said the National Intelligence Bureau was tapping electronic correspondence of top business executives and passing on the information to people close to the government who were profiting from the information.

He said that people were losing confidence after business deals have gone in totally unexpected ways because "it looked like somebody else had inside information".