MILAN (Reuters) - Small shareholders at Telecom Italia (>> Telecom Italia SpA) on Tuesday called on the Italian phone group's board to consider a potential merger between its Brazilian unit TIM Participações SA (>> TIM Participacoes SA) and Brazil's Grupo Oi SA (>> Oi SA).

Shareholder group Asati, which says it represents around 6,000 small Telecom Italia investors with a combined stake of around 1 percent, said in a letter to the board that such a deal could include a "modest" capital increase.

Asati also said that should a merger between TIM and Oi not come about, no offer for the unit should be considered if it values TIM at less than 8.5 times its core earnings.

Sources with direct knowledge of the matter told Reuters on Friday that Oi, Mexico's America Movil (>> America Movil SAB de CV) and Spain's Telefonica (>> Telefonica SA) agreed to place a joint bid worth around 32 billion reais (8 billion pounds) for TIM Participações.

Oi said on Monday it had not entered into any agreement to join a group of rivals to buy Telecom Italia's stake in TIM.

In August Oi announced that it had hired Grupo BTG Pactual to act as its representative and develop plans for a possible purchase of Telecom Italia's stake in TIM Participações.

Telecom Italia's board will meet on Thursday to approve quarterly results. The Rome-based company owns about 67 percent of TIM Participações, Brazil's No. 2 wireless carrier.

(Reporting by Agnieszka Flak and Danilo Masoni; editing by Keiron Henderson)