The Workers' Party (WP) has amended its Constitution in its first major update in six decades.
Cadres voted for changes that include inserting a call for "diverse representation" in its central executive council (CEC).
This replaces a clause stating that cadres must "keep in mind the need for genuine interracial cooperation and the representation of the workers" when electing its party leaders.
WP chairman Sylvia Lim had earlier told The Straits Times that the party has been "reasonably successful" in electing a multi-ethnic team of leaders, but party politics has traditionally been male-dominated, especially in the leadership.
Yesterday, she said that encouraging women to come on board has and continues to be a challenge.
She noted that the new CEC has just two women among its 14 members - herself and former Punggol East MP Lee Li Lian. There was just one other woman - Ms Cheryl Loh - among the 23 candidates who contested.
"It's too few. We have to pull up our socks and give the men a challenge," said Ms Lim with a laugh.
The meeting also deleted references to "colonial exploitation" and "seeking unity of workers of Singapore" in the party's objectives. These were part of WP's founding belief that it would be a party exclusively for trade unionists. It has since widened its reach.
The WP Constitution had not undergone a major review since it was drafted in the 1950s.
A focus group and two open sessions were conducted on the changes, according to a report by outgoing party chief Low Thia Khiang that was circulated yesterday.