Former military ruler retired Gen Pervez Musharraf has been shifted to a hospital in Dubai after suffering a reaction from a rare disease for which he is already under treatment, his party said on Sunday.

The former president was rushed to the hospital as an "emergency" on Saturday night after his condition suddenly worsened, All Pakistan Muslim League (APML) Secretary-General Mehrene Adam Malik said.

APML Overseas President Afzaal Siddiqui told DawnNewsTV that Musharraf had suffered a reaction from amyloidosis, a rare condition for which the former president has been receiving medical care.

"He is expected to be discharged by tonight (Sunday night)," he said.

According to the party, the former military ruler has been advised complete bed rest by doctors till his full recovery. It asked the nation to pray for Musharraf's health.

Siddiqui had disclosed Musharraf's illness in October last year, saying the former president's disease had "weakened his nervous system". At the time, he was being treated for the condition in London.

"Due to amyloidosis, broken protein starts getting deposited in various organs," Siddiqui had explained. "[As a result] Pervez Musharraf has difficulty in standing and walking."

The APML official had then said that Musharraf's treatment could continue for up to five or six months.

Upon his full recovery, Siddiqui had said, Musharraf intends to return to Pakistan.

On March 31, 2014, Musharraf was indicted for suspending the Constitution on November 3, 2007. He, however, left the country in March 2016 for Dubai to "seek medical treatment" and hasn't returned since.