Dr Tan Cheng Bock, a former People's Action Party Member of Parliament and presidential candidate, has been uninvited from a Chinese New Year garden party at the Istana this Sunday.

In a Facebook post on Friday, he said that he received an invitation to the event from the People's Association on Dec 27 last year. Then on Jan 8, he was told by Labour Chief and deputy chairman of the PA Lim Swee Say, that there was a change of policy, and he would no longer be invited to attend.

"He conveyed to me by phone and email. There was a change in 'policy' to invite only those ex-advisers to grassroots organisations, from the immediate past GE (2011). I did not fit into this category as l stood down in 2006," wrote Dr Tan.

The garden party at the Istana is a yearly evening event for grassroots leaders past and present. Dr Tan, an MP from 1980 to 2006, said that since 1980, he has been invited to attend each year and "never failed to go".

"I get to meet grassroots leaders and old colleagues and we exchange warm New Year greetings," he wrote.

"The warm reception usually given me by those grassroots leaders at the function, were overwhelming, more so, after the Presidential election. At times it was very touching.

"Last year I had to be helped to get back into my car because the crowd kept me from moving forward. I shall miss meeting all these friends there again this Sunday."

When contacted by The Straits Times, Dr Tan, who narrowly lost the presidential election in 2011, said that he would "just accept it".

Asked why he decided to share it on Facebook, he said: "So many grassroots people were asking if I would be there. So that's why I wrote it on Facebook, to let them know that I won't."

His post was shared 360 times and liked by over 700 people within an hour of it going up.