More workers have tested positive for coronavirus after an outbreak at a chicken factory on Anglesey.

All staff at the 2 Sisters meat processing plant in Llangefni are self-isolating after a number of workers were confirmed to have the virus on Thursday.

On Saturday the number had risen to 75, Public Health Wales confirmed.

Health officials said the number of cases was expected to rise and samples have been taken from about 350 staff.

Testing sites were set up at Llangefni and Holyhead, and at an existing facility in Bangor, following the outbreak.

All staff and contractors working at the processing plant, which has 560 workers, have been asked to self-isolate for 14 days, and are being contacted for testing.

PHW, who are responding to the outbreak, said the process of taking samples from all workers was "nearly concluded" and "testing was underway".

"What's clear is that the system is working as it should - we are actively screening employees at the facility and this is helping us to identify contacts of individuals who have tested positive for Covid-19," said Dr Christopher Johnson from Public Health Wales.

"The advice for these contacts is to self-isolate to prevent further spread. The aim of the testing is to identify more cases and we're likely to see an increase in overall cases in the coming days."

2 Sisters is one of the largest food producers in the UK and processes about a third of all the poultry products eaten each day from its sites across Britain.

It has suspended production and closed the factory, which supplies local authorities, hospitals, restaurants and small businesses, following the outbreak.

Anglesey council has also confirmed schools will not reopen as planned on 29 June following the outbreak.

2 Sisters had said "the health, safety and well-being of our colleagues is ultimately the thing that matters most at our business".

It added: "We will not tolerate any unnecessary risks - however small - for our existing loyal workforce at the facility."