Tokyo's governor on Wednesday urged residents to avoid non-essential outings and asked businesses serving alcohol to shut early as Japan battles record coronavirus infections.

The country has seen a comparatively small outbreak overall, with just over 2,000 deaths and 135,400 confirmed cases, and has not imposed the strict lockdowns seen elsewhere.

But it is now battling a third wave of the respiratory disease, reporting record numbers of daily infections nationwide in recent days.

"We'd like to ask Tokyo residents, if they can, to refrain from non-essential outings as much as possible to prevent further spread of infection," Governor Yuriko Koike told reporters.

She also encouraged Tokyoites to work from home.

Neither of the governor's new calls will carry any enforcement mechanism. Even a state of emergency declared in the spring during a spike in infections did not carry punishments for those who defied advice to stay home or shutter their businesses.

In addition, Koike asked businesses serving alcohol, including karaoke parlours, to close at 10 pm starting from Saturday for approximately three weeks. Businesses complying will be eligible for compensation.

Koike's announcement came as the Japan Medical Association warned that "medical provision systems across Japan are squarely facing the danger of collapse".

"If the infection count rises rapidly, we will not be able to maintain beds for both coronavirus patients and other patients," said the organisation's president Toshio Nakagawa.

Prime Minister Yoshihide Suga said last week Japan was on "maximum alert" over the virus, and his government has been forced into a U-turn on a controversial domestic tourism campaign.

It initially insisted it would not scale back the so-called Go To campaign, but reversed course and has allowed individual regions to choose to opt out.

So far, hard-hit Osaka and the northern city of Sapporo have been excluded from the programme, which subsidises travel inside the country in an attempt to help the struggling travel and hospitality industries.