India gave the green light for thousands of Sikh pilgrims to cross the border into Pakistan from Wednesday ahead of the birth anniversary of the religion's founder Guru Nanak.

The Kartarpur Corridor, a visa-free crossing allowing Indian Sikhs to visit the temple in Pakistan where Guru Nanak died in 1539, first opened in 2019 for Nanak's 550th birth anniversary but was closed last year because of the pandemic.

India's Home Minister Amit Shah announced that the corridor will re-open from Wednesday ahead of Nanak's birth anniversary celebrations this Friday.

"In a major decision, that will benefit large numbers of Sikh pilgrims, PM @narendramodi govt has decided to re-open the Kartarpur Sahib Corridor from tomorrow," he said on Twitter.

"I am sure that (the) govt's decision to reopen the Kartarpur Sahib corridor will further boost the joy and happiness across the country," Shah added.

A Pakistani official source said the corridor had never been closed on the Pakistan side, and that they were waiting for confirmation from Indian authorities that the pilgrims would be allowed to cross.

Sikh pilgrims collect their passports on the eve of travelling to Pakistan to celebrate the birth anniversary of Guru Nanak
Sikh pilgrims collect their passports on the eve of travelling to Pakistan to celebrate the birth anniversary of Guru Nanak AFP / NARINDER NANU

The white-domed shrine in Kartarpur, a small town just four kilometres (2.5 miles) inside Pakistan, had remained out of reach of Indian Sikhs for decades because of hostile relations between the two countries.

When Pakistan was carved out of India at the end of British rule in 1947, Kartarpur ended up on the Pakistan side of the border, while most of the region's Sikhs remained on the other side.

There are an estimated 20,000 Sikhs left in Pakistan after millions fled to India following the bloody religious violence ignited by partition.

Guru Nanak, born in 1469 to a Hindu family near the present-day Pakistani city of Lahore, is revered both by Sikhs and Hindus who prepare community feasts known as langars to mark his birth anniversary.