The military government of Parkistan has arrested deposed Prime Minister Zulfikar Ali Bhutto and charge him with responsibility for the 1974 slaying of a former parliamentarian's father, the official Pakistan radio said today.

The charges were the first formal action against Bhutto, 49, since Gen. Mohammed Zia ul-Haq seized power from him in a coup July 5, after Bhutto and opposition leaders failed to agree on the merchants for news national elections.

Pressure has been mounting on the military government to move against Bhutto was has been accused of murder, rigging the national elections last March, official corruption, misappropriation of funds and receiving kick-backs on purchases of French military aircraft.

Since his ouster several legal actions have been filed against Bhutto by political opponents accusing him of various abuses of power during his 5 1/2 years in office.

But Bhutto's popularity has remained high despite the coup, and he has attracted large crowds at recent rallies to drum up support for his party in elections scheduled for Oct. 18. He said several days ago that the accusations against him were politically motivated and warned that his arrest would creat a serious situation.

A military spikesman said Bhutto was arrested before dawn today at his villa in Karachi. An official source said he had been taker to Lahore, where a court is hearing a case brought Ahmad Raza Qasuri alleging Bhutto was responsible for Qasuri's father's death.

Qasuri, a former member of Bhutto's Pakistan People's Party, has alleged that his father, Nawab Mohammed Ahmad Khan, was shot to death by federal security officers in November 1974 on the orders of Bhutto, who was then prime minister.

Federal investigators who inquired into Qasuri's complaint after Bhutto was overthrown arrested the officers allegedly involved in the killing. Authorities said the suspects confessed and said that they acted on Bhutto's orders.

Bhutto's arrest - his second since his ouster - comes a few days after he denied allegations by a political opponent that he had accepted $2 million in kickbacks in Pakistan's purchase of French Mirage fighter aircraft, and also got "cuts" on other unspecified foreign purchases.

Other political opponents have accused Bhutto of establishing camps in northern Pakistan where political prisoners were tortured.

Bhutto has also been summoned by the Lahore high court to Sept 13 in two cases of alleged illegal detention of opponents during his rule.

Yesterday authoritites investigating alleged misappropriation of funds seized the books of a trust Bhutto had headed.

Leaders of Bhutto's party planned to meet Sunday to decide what action to take. One of Bhutto's aides said an application for bail would be filed as soon as possible.

A decision to choose a new leader was not excluded, but political sources said it was more likely the party would decide to boycott the election.

A one-sided election could lead to further political instability. Various political sources felt the nine-party Pakistan National Alliance, formed expressly to bring about Bhutto's downfall after the March elections, might split and prove unable to form a strong government. This would comple the army to retain a political role.