Israeli ministers have been told to hand in their mobile phones before weekly cabinet meetings.
Mr Olmert told a minister to get off the phone in a cabinet meeting
The measure is aimed at cutting the number of government leaks which appear in the Israeli press.
In a memo, Cabinet Secretary Oved Yehezkel said mobiles and "other communication devices" would be returned to ministers after meetings.
Local reports say Mr Olmert berated a minister on Sunday for using his phone during a key intelligence briefing.
The unnamed minister was talking on his mobile while the head of the Shin Bet domestic intelligence service, Yuval Diskin, was telling the cabinet about sensitive security issues, according to AFP.
At a news conference after the cabinet meeting, a blackout was imposed on Mr Diskin's briefing.
Mr Olmert's press adviser said it had contained sensitive information "not meant to be exposed to the Israeli public or the Palestinians".
Agency reports suggest it is not unknown for senior Israeli officials to call reporters and leave their mobile phone running during meetings, so journalists can hear what is going on.
Sources from the prime minister's office say the ban on mobiles is one of a series of recommendations from a commission which the cabinet secretary intends to impose strictly.