Former top civil servant Ngiam Tong Dow said he gave the "wrong impression" in a controversial interview last month in which he said current ministers are afraid to speak up and elitist.

On Thursday, Mr Ngiam sent a clarification statement to the editor of the Singapore Medical Association (SMA) News which had published the interview.

In this statement, Mr Ngiam retracted his earlier charge that today's ministers are afraid of speaking up in Cabinet because of their high salaries, saying it was "illogical" and unfair. He also said that ministers are not elitist, as he had spoken without realising many in fact come from humble backgrounds.

"I retired from the civil service in 1999. Since then I have not attended any cabinet meetings, and have never seen one chaired by PM Lee Hsien Loong. Thus my statement that ministers will not speak their minds before PM Lee is unfair as it was made without knowing what actually happens at cabinet meetings today," he said.

"I have been told by civil servant colleagues that cabinet discussions are robust - as robust as they were when I attended cabinet meetings as PS (PMO), when Mr Goh Chok Tong was PM, and Mr Lee Hsien Loong DPM."

Mr Ngiam added that he knows some ministers have given up successful and well-paying careers in the private sector to join politics at lower pay, while others could have chosen to join the private sector to make more money but did not.

"They have no reason not to speak their minds when they are convinced that they are doing right by Singaporeans," he said.

Mr Ngiam also stirred up controversy with remarks suggesting that the certificate of entitlement (COE) system was introduced to "collect more money" for the government.

In his letter, he clarified that "it was not the case".

"The fundamental purpose of the COE scheme was to limit Singapore's car population. If the intent had been to raise revenue, I would not have supported the policy as permanent secretary at the Finance Ministry," he said.

Mr Ngiam is the former chairman of the Economic Development Board and was permanent secretary of several ministries before he retired in 1999.

Here is Mr Ngiam's clarification statement in full:

From the feedback from friends and colleagues who read my interview published in SMA news, September 2013 Issue, it has come to my attention that I had given the wrong impression in several ways.

I had described my discussions with Mr Lee Kuan Yew about the COE scheme as an example of Mr Lee's openness in discussing policies, even with officials. I realise that my comments might suggest that the COE scheme was implemented to raise funds. That was not the case. The fundamental purpose of the COE scheme was to limit Singapore's car population. If the intent had been to raise revenue, I would not have supported the policy as Permanent Secretary at the Finance ministry.

I also realise on re-reading the interview that I had not been fair in what I had said about Ministers and discussions in Cabinet. I retired from the civil service in 1999. Since then I have not attended any cabinet meetings, and have never seen one chaired by PM Lee Hsien Loong. Thus my statement that Ministers will not speak their minds before PM Lee is unfair as it was made without knowing what actually happens at Cabinet meetings today. I have been told by civil servant colleagues that Cabinet discussions are robust - as robust as they were when I attended cabinet meetings as PS (PMO), when Mr Goh Chok Tong was PM and Mr Lee Hsien Loong DPM.

I also realise that my claim that Ministers may not speak up because they earn high salaries is illogical. I know that some Ministers have given up high-flying and well-paid careers in the private sector in order to serve the public at a fraction of their original or potential income. Others could have gone to the private sector to make more money but have chosen to be in the public service. They have no reason not to speak their minds when they are convinced that they are doing right by Singaporeans.

I had also said that the current crop of leaders is elitist. I had spoken without realising that many had in fact come from humble backgrounds.

I had the privilege and honour of working with Mr Lee Kuan Yew, Dr Goh Keng Swee, Mr Hon Sui Sen and Mr Lim Kim San. I have said many times that Mr Lee is my hero and that Singapore was lucky to have had such a team to steer it from third world to first. The Cabinet today faces different and less straightforward challenges, having to deal with globalisation and more intense international competition. However, as I had mentioned in my interview, we are starting from a good position - for example, in healthcare, one of the main subjects of the interview.