British Prime Minister David Cameron on Friday announced new funding worth 5 million pounds (about $7.52 million) for a Commonwealth counter-extremism unit.

The new investment included one million pounds a year for five years to help fund the unit, which is expected to focus on strengthening ability of Commonwealth countries to counter extremism, Xinhua news agency reported.

Cameron also unveiled additional 200,000 pounds funding to expand European counter-radicalisation youth network to include the Commonwealth, according to the Downing Street.

"The fight against extremism is something that affects us all. The Commonwealth has a vital role to play in broadening international efforts to counter extremism," Cameron said .

As part of British government's comprehensive strategy for tackling extremism, Cameron wanted "to increase cooperation with countries around the world to share best practice and identify new approaches to countering poisonous ideologies," a Downing Street statement said.

Meanwhile, the British Quuen opened the Commonwealth leaders' meeting in Malta, saying she was "enormously proud" of the global grouping's achievements over the more than six decades she has been at its head.

The opening ceremony in the Maltese capital Valletta on Friday was attended by representatives from 53 countries, including Australian Prime Minister Malcolm Turnbull.

The Queen said she had come to live in Malta with her husband Prince Philip in 1949 when he was stationed there with the Royal Navy, the same year the Commonwealth was founded, The Australian reported.

She said the Commonwealth was based on shared values and she had been privileged to witness a great advancement in freedom and human rights over the decades. "I feel enormously proud of what the Commonwealth has achieved, and all of it within my lifetime."

The Queen also thanked outgoing Commonwealth Secretary-General Kamalesh Sharma for his eight years of "dedicated service" to the grouping.

In his address, Mr Sharma defended the Commonwealth's relevance, saying it was in "robust good health" and growing in respect and influence as it was given "new and contemporary meaning" for the more than two billion people it represented, The Australian added. He stressed issues of equity and fairness, particularly for small and vulnerable Commonwealth nations.

Climate change is high on the agenda for the leaders' meetings on Friday and Saturday but the fight against violent extremism is also expected to be a key point of discussion in the wake of the Paris terror attacks.