Roth, 59, who adds the chief executive's role to his job as IPG's chairman, is due to have talks with media operating company chiefs this week.
Under David Bell, Roth's predecessor as chief executive and now IPG's co-chairman, the group has lost ground in the media sector.
At the end of last year, IPG's Initiative lost the £680 million Unilever pan-European media account to WPP's MindShare, while Universal McCann lost out in Nestle's $1.5 billion media consolidation to Group M and ZenithOptimedia.
Roth will be anxious to halt the loss of bedrock clients by IPG media shops that began in December 2003 when Starcom MediaVest captured $350 million in US Coca-Cola billings from Universal.
At the same time, IPG has yet to replicate the system used by rival holding companies of setting up a media parent to run its agencies.
Roth must also act to stem creative agency losses, most notably at Lowe which last year lost its global Braun business (£40 million), Verizon Wireless (£170 million), Unilever's pan-European Flora account (£25 million) and the UK Diet Coke assignment (£8.7 million).
Lowe also suffered a huge blow when HSBC consolidated its entire £350 million business into WPP.
- Opinion, p18.