Washington  - Long-time US Senator Ted Kennedy, who has been battling brain cancer since May, was recovering Tuesday after he collapsed in the middle of US President Barack Obama's inaugural lunch with members of Congress, a Senate colleague said.

Kennedy, 76, the last surviving brother of former president John F Kennedy, suffered an apparent seizure towards the end of the private lunch honouring Obama's inauguration and attended by lawmakers and guests including former presidents and vice presidents.

Kennedy was recovering at a Washington hospital and was "in good shape," Senator John Kerry told reporters after visiting Kennedy at the hospital in the evening. Kennedy would spend the night in care but should be released Wednesday, Kerry said.

"I just tell you that he's laughing and joking, right now. He wants to get back to work," said Kerry. Both Kennedy and Kerry represent Massachusetts in the US Senate.

Kennedy, the third-longest serving senator in US history, underwent surgery in June for a malignant brain tumour. He had since returned to work in Congress but on a limited schedule.

Kennedy's collapse put a damper on the celebratory spirits of Obama's takeover of the White House. Obama had been sworn in as the country's 44th president less than an hour before the luncheon.

A visibly shaken Obama said his prayers were with Kennedy and his family.

"I would be lying to you if I did not say that right now a part of me is with him," Obama said in a brief speech inside the chamber, shortly after Kennedy's collapse.

Democratic Senator Jay Rockefeller said the room had fallen silent, the lights dimmed and a crowd formed around Kennedy at the moment of his seizure. Obama himself immediately rushed to Kennedy's side, Rockefeller said.

Kennedy and his niece Caroline, daughter of the slain president, played a key role in Obama's election by throwing their weight behind him in the early days of the bitter battle against Senator Hillary Clinton for the Democratic presidential nomination. (dpa)