PHNOM PENH (AFP) - Cambodia's opposition MPs ended a six-month boycott of Parliament on Tuesday (Nov 22), following months of legal and political pressure from Prime Minister Hun Sen.

Lawmakers from the Cambodia National Rescue Party (CNRP) pulled out of parliamentary sessions in May after some MPs, including its deputy leader Mr Kem Sokha, were slapped with legal cases by the government.

With 2018 elections in view, Mr Hun Sen is increasingly using Cambodia's pliant courts - as well as his political cunning - to box in rivals, a tactic he has deployed throughout his 31-year tenure in office.

On Tuesday, 39 opposition MPs ended their boycott and joined the parliamentary debate on a US$5 billion (S$7.11 billion) Budget for 2017.

"We must return to debate it," said CNRP spokesman and lawmaker Yim Sovann.

He denied his party had caved in to Mr Hun Sen's pressure tactics but said his party "are the victims of (a) political crackdown".

"This (end of boycott) is also a gesture to show that we want a resolution" to the political crisis, he said.

Ruling party officials could not immediately be reached for comment.

The opposition are increasingly cramped in the run-up to elections.

Their leader, Mr Sam Rainsy, is in self-exile in France to avoid arrest on charges which he says are politically motivated.

His deputy, Mr Kem Sokha, has since May been holed up inside party headquarters in Phnom Penh.

He was sentenced to five months in jail in September for refusing to appear in court over an alleged sex scandal.

Last week, an opposition senator was handed a 18-month jail sentence over a defamation case filed by Mr Hun Sen.