Mozambique has sworn in its new parliament with the streets of the capital largely deserted after the opposition leader called for a strike to protest against the result of highly disputed elections.

Two smaller opposition parties boycotted the opening ceremony on Monday as they refused to accept the outcome of the October election, while the incoming president, Daniel Chapo, called for calm and unity after months of deadly unrest.

Opposition leader Venancio Mondlane, who is popular with Mozambique’s marginalised youth, claims the results were rigged in favour of Chapo’s Frelimo party, which has been in power for 50 years.

He urged his supporters at the weekend to “demonstrate our refusal” of the official election result with a national strike from Monday to Wednesday when Chapo is due to be sworn in as president.

Military police surrounded the parliament building and police blocked the main roads to the area during the inauguration ceremony.

The city centre, usually busy on a Monday morning, was deserted with most shops closed and protesters manning barricades in certain areas, the AFP news agency reported.

Al Jazeera’s Fahmida Miller, reporting from Matola neighbourhood, a stronghold of the opposition in Maputo, said people were trying to block a main road into the centre of the capital.

“The aim here by people trying to block the road with burning tyres, with stones – they also throw rocks sometimes – is to stop people passing back and forth on this road and it’s part of the strategy to bring Maputo to a standstill,” she said.

Chapo and outgoing President Filipe Nyusi were present as parliamentarians from Frelimo, which won 171 seats, and the Podemos party – which has 43 – were sworn in to the 250-seat national assembly.

Renamo’s 28 MPs and the eight from the MDM stayed away in protest.

The opening of parliament “constitutes a social outrage and a lack of respect for the will of Mozambicans” who were deprived of “free, fair and transparent” elections, a Renamo spokesman told reporters on Sunday.

The MDM said it was boycotting to show it aligned itself with demands for “electoral truth”.

Official results gave Chapo 65 per cent of the presidential vote compared with 24 per cent for Mondlane.

But the opposition leader claims he won 53 per cent and that Mozambique’s election institutions manipulated the results.

Mondlane returned to Mozambique on Thursday after going into hiding abroad following the October 19 killing of his lawyer.

Thousands of jubilant supporters rallied in the city centre to meet him, prompting clashes with security forces in which at least three people were killed, according to an election monitor.

Unrest since the October 9 election day has claimed about 300 lives, according to a tally by a local rights group, with security forces accused of using excessive force, including live bullets, against demonstrators.

Police officers have also died, according to the authorities.

The unrest has caused major losses to Mozambique’s economy, stopping cross-border trade and affecting shipping, mining and industry.

If “the assembly takes the oath, it is a betrayal of the will of the people”, Mondlane, 50, said via Facebook late on Saturday.

“Let us demonstrate against the inauguration of those who betrayed the will of the people on Monday and against those who stole the will of the people on Wednesday,” he said.

In advance of the opening of parliament, 48-year-old Chapo told reporters that Mozambique needed stability and unity.

With a new parliament in place, “we can continue to work and together, united … to develop our country”, he told journalists, calling for “open, frank debate”.

There have been several calls for dialogue to resolve the standoff but Mondlane has been excluded from talks that Chapo and Nyusi have opened with the leaders of the main political parties.

Mondlane repeated after landing in Maputo on Thursday that he was ready for dialogue. “I’m here in the flesh to say that if you want to negotiate … I’m here,” he said.