More people have been infected by the coronavirus in Singapore's first cluster of local transmission.

The patients now include the Singaporean husband, 45, and the six-month-old baby boy of a 28-year-old Singapore resident working at Chinese health products shop Yong Thai Hang.

Her infection was announced a day earlier, together with that of her Indonesian maid, 44.

The Ministry of Health (MOH) said the baby was not in any infant care facility before he was hospitalised - he was cared for at home.

The 40-year-old husband of a local tour guide who took China tourists to the shop has also come down with the virus, the ministry said yesterday.

It announced four more cases of coronavirus infection here, bringing the total number in Singapore to 28, including seven in the local cluster.

All seven local transmissions can be traced to a tour group from Guangxi in South China, made up of 20 tourists who visited the shop when they were in Singapore last month. Two among the group have tested positive for the virus.

The group had visited various spots in Singapore, and the ministry said it had reached out to 142 contacts, with one person isolated as a suspected case.

MOH noted, however, that there is no evidence of widespread community transmission in Singapore.

On top of the three family members of the tour guide and shop employee, the fourth case announced yesterday is a Chinese national, 42, who arrived here from Wuhan on Jan 21. Her 73-year-old mother, who was also visiting, had tested positive earlier.

The country has put in place multiple lines of defence to prevent the virus from taking hold here.

But the authorities have warned that despite all this, Singapore could still see extensive community spread.

All new cases announced yesterday are stable, the ministry said.

Of the other 24 cases, one has been discharged and the rest are mostly stable or improving. One person needs additional oxygen support, but is not in intensive care, it added.

As of noon yesterday, 295 of the suspected cases had tested negative for 2019-nCoV, as the virus is called, and test results for 62 cases were pending.

Also, MOH had identified 379 close contacts. Of the 304 still in Singapore, all 299 contacted are being quarantined or isolated.

In addition, a Malaysian and two South Korean men who were at the Grand Hyatt Singapore hotel last month had caught the virus.

MOH said they were attending a meeting involving 109 participants from the same company. There were 94 people from overseas, all of whom have left Singapore.

Of the 15 Singapore residents, 11 are well, while four who have reported symptoms have been referred to the National Centre for Infectious Diseases for as-sessment.

The coronavirus first emerged in Wuhan in December and is more infectious than the severe acute respiratory syndrome.

Outside China, which has the bulk of infections, Singapore has the second-highest number of confirmed cases. Japan has the most with 35 cases so far.