India's top court on Wednesday suspended a summons requiring former prime minister Manmohan Singh to appear as one of the accused in a corruption trial involving coal mining licences.

Singh, who was prime minister from 2004 until last year, was the highest-profile figure to be implicated in the case involving the government licence allocations, long dogged by suspicions of corruption.

He faces allegations of corruption-related offences, breach of trust and criminal conspiracy, which carries a possible life sentence.

On Wednesday the Supreme Court agreed to consider challenges by Singh and five other accused, including a former coal minister and a prominent industrialist.

It stayed the summons issued by the trial court.

The 82-year-old enjoyed a reputation for probity during his decade as head of the Congress-led government ousted in last year's general election. He has denied any wrongdoing.

His lawyer Ashwini Kumar said the court had decided to examine the case "since important and substantial questions of law and processes of criminal trial were to be decided".

The Supreme Court ruled last year that there were "legal flaws" in the government's procedure for awarding nearly 220 coal blocks in India, which relies on the fuel for two-thirds of its power generation.

Singh, who also held the coal ministry portfolio during some of his time in office, is one of six people accused by the court over the awarding of the Talabira-II coal block in the eastern state of Orissa in 2005.

They include billionaire businessman Kumar Mangalam Birla, whose company Hindalco Industries won the allocation.