SINGAPORE - The National Solidarity (NSP) party's former chief, who recently left his post, has quit the party.

Lawyer and former NSP secretary-general Tan Lam Siong said he has parted ways with the party he led for about five months, and plans on running as an independent candidate in the next general election.

He said he has plans to contest Whampoa single-member constituency, currently under People's Action Party Member of Parliament Heng Chee How.

Mr Tan, who joined the NSP two years ago, had been elected to the post of secretary-general at the party's biennial central executive committee election in January.

He stepped down in June, citing "incompatibility issues", but remained part of the party's top decision-making body. Ms Hazel Poa, a former government scholar and 2011 election candidate, was appointed acting secretary-general to take his place.

Speaking to The Straits Times about his decision to leave the party completely, Mr Tan said: "If I were to continue in NSP, it will be something which I would feel uncomfortable with. There are certain ideologies I have that are not completely matching (with the party's). I would prefer to be free of these concerns and to have greater freedom."

He added that he was leaving the party on friendly terms, and had sent a text message to NSP president Sebastian Teo to wish him well.

NSP has had four different secretary-generals since 2011, and also saw a spate of resignations during the same period, sparking talk of possible rifts within the party.

This year alone, the party has lost six members, including Mr Tan.

Mr Tan declined to comment on the party's matters, adding: "There's already a lot of politicking in the political arena. I find it quite upsetting that people regard one another as foes rather than as comrades."

On his choice of Whampoa, he said he has been doing community and social work in the area and is familiar with the issues that residents there are facing.

"I've also not met anyone else walking Whampoa, so it seems like nobody else is interested other than the incumbents," he said.

He added that he had turned down offers to join other parties, and would run as an independent candidate in the next election.

"I may consider setting up my own party in future to develop further into politics...but not for the next election," he said.