Luncheon Star, a local food supplier serving more than 200 schools and 100,000 lunchboxes, announced last week that it would halt its school meals service on Monday and Tuesday for factory inspection, as three pupils reported feeling sick after eating their products.

"More than 500 students were affected today," said Hung Wai-shing, principal of SKH Tin Shui Wai Ling Oi Primary School.

"Many parents have prepared lunch to send to classrooms or ask students to carry with them before school," Hung said, "some pupils also dined in fast-food restaurants."

"These are temporary measures and we urged the investigation on Luncheon Star would be unveiled soon," Hung added, noting the school meals provider failed to provide solutions for supply suspension.

A school in Tsing Yi invite parents to take over the chefs' roles to prepare meal boxes for the 200 students.

Students from the Holy Cross Lutheran School in Tsuen Wan even enjoyed a surprise picnic as they were taken to Inspiration Lake next to Disneyland.

Tang Fei, a lawmaker and the vice-chairman of the Hong Kong Federation of Education Workers, said some schools might lack response measures to the supply suspension as no food poisoning case has happened before.

"It is necessary for other food suppliers to take part and the education authority needs to approve emergent tenders for schools to seek other suppliers," Tang said.