David Cairns MP, chairman of Labour Friends of Israel, has died following a short illness.
Mr Cairns, who was 44, was taken ill in March suffering from pancreatitis. He died on Monday night.
The Inverclyde MP, a former Scotland Minister, was serving in his second spell as chairman of the group. He previously held the role in 2004 before returning in October last year.
Mr Cairns was first elected to Parliament in 2001, having earlier trained as a Roman Catholic priest.
Jennifer Gerber, LFI director, said: "We are deeply saddened by David Cairns' tragic and untimely death. David was a bright, generous and extremely kind man, and an inspiration to all fortunate enough to have known him.
"LFI was extremely lucky to have enjoyed his generous and dedicated support as chair on two occasions, and will endeavour to ensure that the positive impact he had will be remembered and honoured.
"We especially remember how caring and supportive he was, and also how much we enjoyed his warmth and sense of humour."
Labour leader Ed Miliband said: "David will be missed beyond measure as a former minister, as an MP, as a friend and a colleague by many people and my heart especially goes out to his partner Dermot and his family in Scotland.
"He brought a sensitive understanding of others and a ready wit to politics, and he never shied away from saying what he believed to be true. He was a good man."
The Board of Deputies said his death was "terribly sad".
Paying tribute to Mr Cairns, the Jewish Leadership Council said: "The JLC mourns the passing of David Cairns MP, an exemplary public servant and staunch friend of Israel and the Jewish community."
Jamie Reed MP said: "David Cairns was one of the best people I have ever known and ever will know. The country is poorer for his passing - he made this place better."
Labour MP Stella Creasy wrote on her Twitter page: "Went to see David Cairns in hospital - thought he was getting better so I'm gutted by today's news. A lovely man - honoured to have known him."
Liberal Democrat MP Julian Huppert said: "David was one of the first MPs I met here [in Westminster], and was friendly and active in many areas."
Israel's ambassador to the UK, Ron Prosor, said his death was a great loss. "David was a proud friend of the Israeli people, who stood staunchly by our side, never taking the easy way out."
Mr Prosor added: "He often told how his colleagues in Parliament would urge him to be a more ‘critical friend’ – their emphasis always more on the ‘critical’ than the ‘friend’.
"It is a mark of the man that in spite of this, he never saw the need to dilute his support. He was a true friend."