Minister for Transport, Tourism & Sport Leo Varadkar has said that there needs to be diversity of ownership in the Irish media.
He said his concern in the longer term is that people will start to lose trust in the media.
The latest Edelman Trust Barometer, he said, showed that trust in media is declining while trust in the Government is rising.
Speaking before he went into the MacGill Summer School, the minister said that no one group should have dominance in the media.
He said RTÉ, for example, is very dominant on the airwaves and on television more than any democracy would like.
The growth of Communicorp and Denis O'Brien's holding in the press and radio also needs to be considered, he said.
The summer school is discussing the media and democracy today.
Editor of The Irish Times Kevin O'Sullivan said that social media has disrupted robust news gathering.
"Many in the new camp of 'breaking news' don't apply the same value system as the big established players'', he said.
''This has helped fuel a mistaken view that 'old fashioned' news gathering and verification is of less merit.
''It has been described elsewhere as 'abandoning journalism for the tyranny of the click'.''
