A further 19 agricultural workers have tested positive for Covid-19 on a farm which went into lockdown last weekend.
Herefordshire vegetable producers AS Green & Co was forced to go into lockdown after the outbreak, which initially infected at least 73 crop pickers.
Herefordshire Council and Public Health England (PHE) said the number has increased to 93 on the Mathon-based farm. Further testing is ongoing.
Two groups of farm workers who came to the UK via bus and plane, some of whom worked at AS Green & Co, are now being traced as a precaution.
The council and PHE explained that those who tested positive for the virus were not showing symptoms on entering the country.
The joint statement added that Scottish authorities were now investigating a group of 63 workers who were on the same flight as the AS Green workers.
No Covid-19 cases have been identified among a further 76 people on the flight who travelled to other farms in England.
Karen Wright, director of public health for Herefordshire, said: "We continue to test workers at the farm and expect to see the number of cases rise over the coming days before social distancing and infection prevention measures start to take effect.
"Workers have been asked to remain on site and self-isolate to reduce risk of spread within the workforce and into the wider community.
"We’re aware that local residents are concerned, but the risk to the general public remains low."
She added: "We are arranging food and essential supplies to the farm and its workers during the period of isolation."
The government has issued Covid-19 guidelines on working safely in the agricultural industry.