The labour provider, which operates SAWS, has suggested that a successor to the scheme - set to be phased out by 2010 - should incorporate workers with the Government's Tier 3 and Tier 5 visas.
Both visa types are temporary. Tier 3 visas are granted for a maximum of a year for low-skilled workers from outside the EU whose employers have had difficulty sourcing labour domestically. Tier 5 visas are for people aged between 18 and 30 who are on cultural exchanges or working holidays in the UK.
HOPS general manager John Yates said: "Seasonal labour is and will be an essential and valuable resource for some time to come.
"We must not let our Government legislate against the industry acquiring the labour that is so essential to ensure the UK industry can compete in a wider market and against imports."
He added: "There is no logical reason why quota should not increase up until A2 (Romanian & Bulgarian) workers have free access, then SAWS or its successor should permit a wider sourcing of critical labour from outside the EU using Tier 3 and Tier 5 of the points-based system."
"(Otherwise) fresh produce will unfortunately be shipped in from further afield.
"Locally grown crops will be cereals and oil seeds, allowing the important local fresh vegetable and fruit industry to shrink further or, worse still, reduce the length of the local season."
The Government has restricted SAWS to workers from just Bulgaria and Romania - both of which have recently joined the EU.
It has also restricted it from 25,000 workers to just 16,250.
Both moves are part of a plan to phase out SAWS completely by 2010 in order to prevent the kind of high-level immigration experienced in the UK the last time a group of eastern European countries joined the EU.