Over 3,000 people have visited the Lee Kuan Yew memorial exhibition at National Museum as of 3pm on Good Friday.
Chinese daily Lianhe Zaobao reported that the public started to queue outside the museum from 10am.
National Museum's latest twitter update at 11.30am estimated a two-hour waiting time for viewing the exhibition.
The museum has deployed staff to manage the crowd at the Glass Atrium on the museum's second level as it can only accommodate 250 people at any one time.
Due to safety reasons, museum staff are allowing groups of 15 visitors to view the exhibits of Mr Lee's red box, barrister wig and Rolex watch at three-minute intervals.
The museum has also started a priority queue for the elderly, pregnant and the disabled.
On Thursday, National Museum announced the red box as a new addition to the display at the exhibition.
Minister for Education Heng Swee Keat, who served as Mr Lee's principal personal secretary from 1997 to 2000, said in a March 24 Facebook post that the red box was a symbol of Mr Lee's dedication to the country, as he had used the box every day until Feb 4, the day before he was hospitalised.
Mr Lee died aged 91 on March 23 and Singapore went into a week of national grieving.
In Memoriam: Lee Kuan Yew is open daily from 10am to 8pm at the Glass Atrium, Level 2, National Museum of Singapore until April 26.
Admission to this exhibition is free.