PML-N President Shehbaz Sharif on Wednesday said that because former prime minister Nawaz Sharif's daughter, Maryam Nawaz, was not permitted to be with him in London, cardiologists had to change the pre-decided date for his treatment twice.

In a statement, the Leader of the Opposition in the National Assembly said it was very unfortunate that Maryam was not being granted permission to take care of her father.

He said purely on the basis of humanitarian grounds, the PML-N vice president should be permitted to be with her father.

The PML-N supremo is currently in London for medical treatment. While Maryam had sought permission to fly abroad to be with her father, the federal cabinet in December last year decided not to remove her name from the exit control list (ECL) in the Al Azizia Steel Mills reference.

On January 14, the federal cabinet placed her name on the ECL for the second time in the Chaudhry Sugar Mills case.

"As Nawaz's health is concerning, the margin for medical action is reducing as more time passes," Shehbaz said.

He said cardiologists had to twice change the earlier decided date for his brother's cardiac catheterisation as Maryam was not with him.

Beginning his statement, the Leader of the Opposition said Nawaz's health remained worrisome and unstable.

"The necessary process for his treatment had to be changed twice because his daughter Maryam Nawaz, who wants to be with her father at such a time, has not been allowed to come [to London] from Pakistan," he said.

Further, Shehbaz said that Kulsoom Nawaz's death had a "severe negative effect" on Nawaz's health.

He added that Maryam had been a source of comfort, ease and strength for her father during this time.

Meanwhile, Nawaz's personal physician Dr Adnan Khan said that the former prime minister, after intensive investigations, was found to have "complex multi-vessel coronary artery disease and substantial ischemic and threatened myocardium".

In a tweet on Wednesday, he highlighted that Nawaz was scheduled to undergo a procedure last week. However, the procedure was delayed as Maryam was not allowed to travel.

"Now, once again, the procedure is being postponed for a later date for the same reason."

He stressed that "any undue delay is taxing on [Nawaz's] health and could have adverse consequences". "Maryam must be with her father at the time of this complicated, high risk cardiac intervention," he added.

The jail sentence of Nawaz, who was serving a seven-year prison term in the Al-Azizia reference, was suspended by the Islamabad High Court on medical grounds for eight weeks in October last year. He was also granted bail by the Lahore High Court in the Chaudhry Sugar Mills case on medical grounds and subsequently allowed to travel abroad for treatment.

On December 23, Nawaz sought an extension in his stay abroad on the expiry of the four-week period granted by the Lahore High Court. Following his request, the Punjab government constituted a four-member committee to decide on it and sought fresh medical reports to make an "informed decision".

Earlier this month, a picture of Nawaz at a London restaurant along with some members of his family had surfaced on social media, raising questions about the condition of the former premier's health. Following this, on January 15, the Punjab government had rejected Nawaz's medical reports which had been submitted on December 23.

Once again on January 30, the Punjab government asked Nawaz to submit fresh medical reports so that a decision on his request seeking more time abroad could be made.