Members of the public who want to write a get-well message for Her Royal Highness Princess Bajrakitiyabha Narendiradebyavati will get another opportunity to do so.
The Royal Household Bureau has decided to allow well-wishers to pay tributes to the princess for two more hours each day.
Those wishing to pen messages for the princess can now do so between 8am and 6pm every day at Bhumisiri Mangkhalanusorn Building at King Chulalongkorn Memorial Hospital.
People on Sunday continued to turn up at the hospital to write messages for the princess and present flowers before the princess' portrait at the hospital.
They included Chinese ambassador Han Zhiqiang, Pattaya City Mayor Poramate Ngampichet, the Thai-German Society, the Office of the Royal Society, the Ministry of Foreign Affairs and Nakhon Ratchasima Rajabhat University.
Former prime minister Anand Panyarachun, who was also among the well-wishers who came on Sunday, said the princess has always paid attention to people's well-being.
"Her works are aimed at easing the people's plight and bringing happiness to them. Thais are joining together as one to pray for her speedy recovery,'' Mr Anand said.
Princess Bajrakitiyabha is being treated at King Chulalongkorn Memorial Hospital after losing consciousness due to heart problems last Wednesday.
The princess passed out while training her pet dogs at 6.20pm in Nakhon Ratchasima's Pak Chong district last Wednesday.
The dogs were being trained as they were slated to take part in the Thailand Working Dog Championship organised by the Royal Thai Army, which ends today.
The princess was initially taken to Pak Chong Nana Hospital, where medics administered first aid under the advice of royal physicians.
Once her condition had stabilised, she was airlifted to King Chulalongkorn Memorial Hospital in Bangkok.
Several Thai embassies abroad organised chanting sessions and merit-making activities for the princess' recovery on Sunday.
The Thai embassy in Canberra, Australia, held a chanting session at Wat Thammatharo.
Officials at the Thai embassy and the Thai community in Prague, Czech Republic, also took part in a chanting session at Wat Thamkittiwong.
The Royal Thai Consulates-General in Chicago and Sydney also held a chanting session for the princess.
