More members of the government than previously thought knew that tens of mobile phones were tapped before the matter was made public, sources told Sunday's Kathimerini.

Authorities, meanwhile, are growing increasingly convinced that the suicide of a Vodafone engineer had something to do with the case.

Sources said that three more government officials - apart from the prime minister, government spokesman Theodoros Roussopoulos, Justice Minister Anastassis Papaligouras and Public Order Minister Giorgos Voulgarakis - knew about the phone-tapping since March last year.

The revelation is only likely to heap more pressure on the ruling conservatives, who have been criticized for their inactivity in finding out more about the phone taps over the last 11 months.

Premier Costas Karamanlis is to attempt today to reverse the tide of negative opinion by saying he will tighten regulations and introduce stiffer penalties for mobile phone companies.

The delay in informing the public has proved unpopular with voters. A poll by Alco, published in yesterday's Proto Thema newspaper, indicated that between 44 and 48 percent of voters think that Roussopoulos, Papaligouras and Voulgarakis should resign.

High-ranking government sources said that there is growing suspicion about the death of Vodafone software engineer Costas Tsalikidis and that it was linked to the mobile phone tapping.

Tsalikidis allegedly committed suicide by hanging himself on March 9 - two days after the spy software was discovered and one day before Vodafone CEO Giorgos Koronias informed the government that around 100 numbers had been bugged.

It has emerged that the software had always been part of Vodafone's central system and could be activated at any point to allow authorities to monitor phone calls for security purposes.