It is ironic that instead of helping the DAP meet its political ambitions as allies in the Pakatan Rakyat coalition, PAS is turning out to be the DAP's greatest hindrance.
As the DAP takes inclusive steps, encouraging more women to participate, attracting more Malays to its ranks and using Bahasa Malaysia instead of Chinese, PAS is acting as a brake to DAP's ambitions.
And while the two parties constantly bicker over many issues, including Islamic law and lifestyle, PKR is silent and praying that the storm will blow over and not damage the coalition.
But relations between PAS and DAP have become so frosty in recent months that matters will come to a head, sooner than later.
"Don't be surprised if there is a parting of ways ... We are deeply concerned over our partner's behaviour and are worried about the impact," said a DAP central working committee member who requested anonymity.
"PAS is no longer "PAS for all" as was their slogan in last year's general election.
"It is now more conservative and too hardline for us. We will not hesitate to sever links with PAS to protect our support base (the Chinese)," he said, referring to the time the DAP parted ways with the Barisan Alternatif coalition in September 2001.
The feeling is mutual - PAS feels the same way about the DAP.
PAS president Datuk Seri Abdul Hadi Awang told his liberal party members or "Anwarists" in August during the Selangor mentri besar crisis to either toe the party line or leave.
Also, he did not toe the Pakatan coalition line or heed his own central committee when he refused to back PKR president Datuk Seri Dr Wan Azizah Ismail for the mentri besar post.
After that, PAS' relations with the DAP steadily deteriorated, with Hadi declining to meet Lim Guan Eng or Lim Kit Siang face-to-face while Anwar continued to paper over the gaps.
Hadi also stopped attending Pakatan's presidential council meetings, with the DAP secretary-general making appeals urging him to attend.
The DAP central executive committee even passed a resolution urging Hadi to attend council meetings and to preserve Pakatan's unity.
But all to no avail.
Hadi said he would attend if he wanted to attend while his men were more apologetic, saying that he was either busy or sick.
The situation has become so bad that leaders are now mutually suspicious of each other.
"Before there was genuine camaraderie, but now we look at PAS leaders, especially the ulama faction, with deep suspicion," said a DAP veteran who declined to be named.
"We cannot look at them the same way again."
He said PAS' behaviour during the mentri besar crisis had sparked off the bad blood between both parties.
DAP adviser Kit Siang sounded a warning last week. He said the Pakatan coalition may not survive to challenge Barisan Nasional in the next general election because its leaders cannot see eye-to-eye and have not met in the past six months.
Even worse for the DAP is a decision by PAS to table the Syariah Criminal Code(11) Enactment 1993, concerning hudud on Dec 29. It is like waving a red flag in front of a bull.
The DAP has told PAS to give up on hudud because Malaysia is a multi-ethnic society governed by secular laws.
The DAP has also said to PAS in no uncertain terms that it will never accept or condone hudud, which allows the amputation of hands for stealing and the stoning to death of offenders for adultery.
PAS being a religious party, however, cherishes hudud as God's law. It is championing for hudud's implementation not just in Kelantan, but in the whole country.
It has the approval from Minister in the Prime Minister's Department Datuk Seri Jamil Khir Baharom to set up a joint technical committee to study all aspects of hudud's implementation.
PAS is keen to keep its traditional constituents - conservative rural Malay voters - for whom Islam is paramount. PAS also portrays itself as a diehard champion of the religion.
A rift between PAS and DAP has appeared once before and had led to a parting of ways and which no amount of papering-over could conceal.
One delegate at a just concluded DAP convention put the party's dilemma succinctly.
"Pakatan is a trishaw. It needs all three wheels to move forward," DAP Socialist Youth leader Damien Yeoh said in his speech at the event.
"Some argue that we can move on two wheels," he said.
"But with two wheels you may fall down.
"Three wheels is better," he said, referring to the DAP, PAS and PKR.
But this is a dilemma that the DAP finds extremely difficult to resolve.