Belgium said Wednesday it wants to boost its coronavirus testing fivefold, to 10,000 per day from the 2,000 currently which some doctors judge to be gravely insufficient.

Philippe De Backer, the minister tasked with coordinating the effort to slow the virus's spread, said in a statement that goal should be reached "in the coming days".

But he stressed testing would continue to be carried out on hospitalised patients exhibiting symptoms.

"It does not make sense to people at the doctor's or even people who show up at hospitals asking to be tested for COVID-19," he said.

Belgium, like other countries, does not have enough kits to test widely for the virus and so is concentrating on only the most acute cases so far.

But hospitals, labs and are ramping up their capacities to broaden the effort to better identify epidemiological transmission and isolate carriers.

De Backer said they were making "a titanic effort" to meet that demand, pointing to two Belgian companies, Biogazelle and Coris Bioconcept, on the frontline of the effort.

The first company, located in the city of Ghent, is promoting an automatised technique called PCR testing that is endorsed by numerous university researchers because it requires fewer difficult-to-source reactives in its process, his statement said.

The second, Coris Bioconcept, located in the country's south, has a rapid antigen test suitable to sort hospitalised patients and meeting EU medical norms, he said.

Belgium currently has nearly 5,000 infection cases counted and 178 deaths. Authorities acknowledge the spread in the population of 11 million is much bigger but cannot be ascertained without widespread testing.

Two doctors at Brussels' main university hospital last weekend wrote a letter to Prime Minister Sophie Wilmes calling it "unacceptable" that only a fraction of patients with symptoms and were being tested because of lack of kits.