There will be no immediate shift in Pakistan's military policy under the new army chief, the country's defence minister said, after Prime Minister Nawaz Sharif appointed a new military leader on Saturday.

Lieutenant General Qamar Javed Bajwa will replace retiring army chief Raheel Sharif when his three-year term ends on Tuesday, a rare example of a smooth transition in a nation where army chiefs have a history of clinging to power.

General Sharif, who is not related to the prime minister, has proved popular with ordinary Pakistanis but during his tenure relations between the army and the civilian government have often been tense.

Relations abroad have also frayed, with the United States and Afghanistan complaining of a lack of action by Islamabad against Afghan Taliban militants based on Pakistani soil, while a stand-off with old foe India over Kashmir has soured relations.

Bajwa was one of several high-ranking candidates put forward for the job by the army but little is publicly known about him or his ideological stance on key issues, including relations with India or how to tackle home-grown Islamist militants.

Defence Minister Khawaja Asif dampened any expectations that Bajwa would immediately push for a radical policy shift.

"The military policy will continue and there will be no immediate change in it," Asif told Geo News TV channel.

"The legacy of General Raheel Sharif would continue in the light of the examples he set," Asif added.

Security in Pakistan has vastly improved during General Sharif's tenure, but the country remains vulnerable to internal strife, with Islamist militant groups carrying out major bomb and gun attacks. In recent months a hospital, a mosque and a police training college have been targeted.

Islamic State, which has claimed several large-scale attacks in recent months, is also trying to establish a foothold in the nuclear armed nation of 190 million people.

The United States on Sunday issued a statement welcoming Bajwa's appointment and said it wanted to assist Pakistan with its domestic and regional counter-insurgency and counter-terrorism efforts.

In a statement, the U.S. embassy in Islamabad also said it wanted to help "Pakistani authorities to honour their pledge to prevent the use of Pakistan's soil for terrorist attacks against its neighbours".

India has in recent months sought to isolate Pakistan after an Indian army base in the disputed Kashmir region was attacked and 18 soldiers killed in a September raid that New Delhi blames on Pakistan-based militants. Islamabad denies involvement.

INDIAN ARMY CHIEF PRAISE

General Sharif will become the first army chief in more than 20 years to step down at the end of his term. Previous army chiefs have either obtained extensions or in the case of General Pervez Musharraf, staged a coup.

One cabinet minister told Reuters Bajwa was chosen because of his low-key approach and a belief by Prime Minister Sharif that he would shun the limelight, in contrast to his predecessor, while ceding more policy space to the civilian government.

The army plays a big role in Pakistani politics, including dominating foreign policy strategy on key areas such as relations with India, Afghanistan and the United States. The military also runs a vast business empire.

Zahid Hussain, a security analyst, said heightened tensions with India, kept inflamed by fierce cross-border shelling in the Kashmir region, means in the short term the army was likely to maintain a tight grip on foreign policy issues related to India.

"Since the tension is so high, Nawaz (Sharif) is not in a position to manoeuvre out of that," Hussain said.

Bajwa, who was first commissioned in the army in 1980, has served in Kashmir and other regions bordering India but it is not clear if he will take a less hawkish approach to Pakistan's historic foe.

General Bikram Singh, a former head of India's army who served with Bajwa in the Congo as part of a United Nations peacekeeping force, praised Bajwa's conduct as a soldier during their time in Africa.

"In the international environment, his performance was professional, outstanding," Singh told India Today TV channel.

But when reporters asked Singh if he expected Bajwa to alter Pakistan's military policy, he said: "I do not see any change".