David Cameron has arrived in Malaysia where he will challenge his counterpart Najib Razak over allegations of corruption which have triggered a political crisis in the country.

The Prime Minister insisted it was "absolutely right" for him to visit, but said his trip would also include meetings with anti-corruption campaigners and opposition figures.

In a hastily-arranged change to the schedule a senior member of Mr Cameron's official party will meet the family of a jailed opposition leader.

Mr Najib, who has faced allegations that he received about 700 million US dollars (£448 million) in government money, has sacked both the attorney general who had been investigating him and his own deputy, who had been a prominent critic.

Leaked confidential documents obtained by the Wall Street Journal allegedly show the money, from state investment fund 1MDB, went into his personal accounts.

Mr Najib, who has claimed the attack against him is politically motivated, has not disputed the existence of the accounts or the receipt of the funds, but has insisted that he never used public money for his personal gain.

The Malaysian leader has also been accused of clamping down on any opposition, with the publication of a newspaper being suspended by the state over its coverage of the 1MDB scandal.

The Prime Minister, who has used his south-east Asian tour to campaign against the "cancer" of corruption, told reporters accompanying him on the trip: "It is absolutely right to go ahead with these visits. The issues of corruption are issues in this region as elsewhere in the world.

"I don't think it helps not travelling to a country and turning away. It is better to go and talk about these things."

He added: "It is right to go ahead with the visit, but nothing should be off the table we should talk about these issues including the specific ones now.

"We always have discussions with civil society figures, anti-corruption campaigners, opposition leaders and all the rest and that will happen on this visit too."