The commercial television networks have refused to screen advertisements lambasting the federal government over Timor Sea oil and gas negotiations, East Timor advocates said today.

The ads, bankrolled by Melbourne businessman Ian Melrose, depict World War II diggers verbally attacking Prime Minister John Howard over the talks with Australia's tiny northern neighbour.

Negotiations, drawn out over the past year, have stalled repeatedly over a disputed maritime boundary.

Australia has been accused of playing hardball over the resources - worth an estimated $41 billion.

Canberra wants the boundary set back closer to East Timor and is seeking most of the royalties from the Greater Sunrise gas field, worth about $9 billion.