The Australian government’s smartraveller.gov.au advisory for travellers doesn’t say it. But it’s time to speak bluntly: Do not enter or go near anti-government protest sites in Bangkok. And do not travel around the city late at night.

Every day for the past week I have seen tourists, including Australians, wandering through protest areas, seemingly oblivious to the dangers. Some of them had children with them.

As the sun rises across Bangkok this morning the extent of the night’s battles remains unreported. It was too dangerous for journalists to venture on to the dark streets.

But since last Friday there have been dozens of reports of violent incidents and at least six grenade attacks that left four children dead and more than 60 people injured.

The worst attack was on Sunday night in the middle of Bangkok’s commercial and tourist centre. A five-year-old boy and his six-year-old sister were killed and almost 30 people were injured, some seriously, by a grenade.

Speaking at a shrine of flowers and toys for the children, Australian tourist Bernadette Bakker said she had no idea of the danger when she asked a taxi driver to take her around the protest sites.

"We did not realise that where we are standing children had died," said Ms Bakker from the Gold Coast as she fought back tears. There should be better warnings for travellers, "something should be put up at the airport," she said.

Russian tourist Julie Kochukova was also shocked to learn she was walking past a shrine where children had died and there had been several attacks.

"Now I am scared...maybe now we will go up the street and go out," she said, pushing her toddler daughter in a pram.

The area is near several of Bangkok’s largest five-star hotels and ritzy shopping malls popular with tourists. One of them, Central World shopping centre, was largely destroyed when it was firebombed during bloodshed in 2010.

Since then the United Nations Children’s Fund (UNICEF) has urged the Thai authorities, anti-government protesters and parents to protect children by keeping them away from all protest sites.

Bijaya Rajbhandari, UNICEF’s representative in Thailand, said areas within and around protest barricades should become “child free zones” to ensure there are no further fatalities or injuries among children.

Some countries have warned their citizens to stay away from Bangkok. Hong Kong even issued a “black'' (severe) warning threat for Thailand (Bangkok), which prompted criticism from tourism operators that it had gone too far.

Thailand’s Tourism Ministry reports that tourist arrivals in January dropped by 1 million from the same time last year, costing the country millions of dollars in lost revenue. Thailand remains one of the most popular destinations for Australian tourists (450,000 visited in the year to June 2013), particularly the resort island of Phuket where before the crisis an average 20,000 Australians tourists holidayed each month.

While tourist operators on Phuket report that the number of Australians coming to Phuket at the peak of tourist season in December and January appeared to have dropped only slightly, the number of tourists arriving from China and Japan has dropped by as much as 90 per cent.

Australia's smartraveller.gov.au advisory for Thailand has not been updated since February 19. It says that, overall, travellers should exercise a “high degree of caution” in Thailand, one of the most popular travel destinations for Australians.

“We continue to advise travellers to avoid all protest sites and surrounding areas, political rallies and processions through Bangkok and in other locations, political events and large-scale public gatherings due to the risk of further violence and terrorism,” it says.

It should read “do not enter” the sites under any circumstances.

Since protests began last November, 21 people have died and more than 800 have been injured.  Thailand's military has warned that the country could face collapse unless urgent action is taken to end escalating violence.

Asked about not updating the travel advisory, a spokeswoman for the Department of Foreign Affairs said Wednesday: "We believe the travel advice remains appropriate at this time." She said the advice is kept under close review and "we will promptly reissue the travel advice as required."