Talks between the EU and Norway are due to get under way on the issue on Monday but the Shetland Fishermen's Association said that existing quotas were already "inadequate" in an area in which fish stocks were abundant.
Simon Collins, executive officer of the association, said: "No one wants to see perfectly healthy, high-quality fish dumped back into the sea, dead. But in accordance with multi-annual plans devised before the discard ban materialised, the European Commission is proposing cuts in already inadequate quotas.
"Not for the first time, quotas are simply failing to catch up with what is happening on our fishing grounds. And the result is discarding for purely regulatory reasons.
"It is bitterly ironic to hear the commission arguing for quota cuts that would necessarily lead to more discards. Is it serious about tackling discards or not?"