As it stands, the two companies own 45% of TV3 each, with the remaining 10% owned by minority shareholders including U2 manager Paul McGuinness.
Under an existing shareholder agreement, ITV is believed to have first refusal on the CanWest stake, which is understood to be worth up to £75m.
If ITV turns down the stake, Irish sports broadcaster Setanta and UTV, owner of the ITV franchise for Ulster, would be potential candidates for the stake.
TV3 launched in 1998 and secured an 11% of viewing last year compared with 27.8% for state broadcaster RTE One, which is Ireland's biggest channel.
Canadian media group CanWest is believed to be selling its stake to reduce debts. It has appointed investment bank Hawkpoint Partners to handle the sale.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .
.jpg)
.jpg)