Zardari, who co-chairs the PPP, had earlier met Sharif in London on Thursday, after party aides in Pakistan failed to patch up differences with Sharif's party.
Farooq put the blame of the deadlock on the PPP.
"Of course we do not support a judiciary which is subservient to the executive," Farooq said, adding that Sharif would return to Islamabad on Monday morning.
Farooq also said that his party would not agree to a "pick and choose" solution for the issue.
Farooq declined to say whether his party would quit the coalition, which came to power after the PPP and the PML-N trounced Musharraf's allies in the February general elections.
When asked if the May 12 deadline would pass without the reinstatement of the judges, Farooq said: "There is no session of the national assembly tomorrow."
Earlier, Sharif had said that the national assembly will approve a resolution on May 12 and on the same day, the judges would be officially restored.
However, Farhatullah Babar, PPP spokesman, downplayed reports of the deadlock and said there was hope since progress had been made.
Babar said that party stalwarts from both sides held meetings till late Saturday night and had "narrowed down" differences over the reinstatement of judges and the independence of judiciary.
"I cannot call it a deadlock. Some proposals have been exchanged," Babar said.
Babar also confirmed that the national assembly was not meeting on Monday.
The reinstatement of the judges is likely to cause a problem for Musharraf, who considers them hostile.
Musharraf dismissed around 60 judges after imposing a six-week emergency rule in November, in order to pre-empt a ruling against his re-election in October.
It is possible that if reinstated, the judges could revive the case against Musharraf's re-election.
Sharif, the prime minister overthrown by Musharraf in a coup in 1999, wants the judges restored immediately, but Zardari wants to avoid immediate confrontation with Musharraf.
The PPP instead favours linking reinstatement of the judges to a constitutional package and also wants to sideline Iftikhar Chaudhry, the former chief justice of Pakistan's Supreme Court.