Sri Lankan Prime Minister Ranil Wickremesinghe resigned from his post on Wednesday, Xinhua reported citing the prime minister's office.

His resignation comes after his party's presidential candidate Sajith Premadasa lost a presidential election over the weekend, according to his office.

The government information department said Wickremesinghe will inform newly-elected President Gotabaya Rajapaksa in writing of his decision to step down from his position. 

The decision was reportedly taken to facilitate Rajapaksa to form his own government after he won last Saturday's presidential elections, the government information department added.  

Rajapaksa won the elections by securing over six million votes, defeating ruling party candidate Sajith Premadasa who secured over five million votes. 

Soon after Wickremesinghe's party lost the election at least 10 of his senior ministers, including finance minister Mangala Samaraweera, resigned. 

The current parliament was elected in August 2015 for a five-year term and cannot be dissolved by Rajapaksa until March, six months before its term ends.  

However, legislators through a majority resolution could ask for a snap poll. Rajapaksa's party does not enjoy a majority in the 225-member assembly and must depend on Wickremesinghe's United National Party to form a minority government until the next parliamentary election. 

Under the Sri Lankan constitution, Wickremesinghe's government will be dissolved following his resignation.

Rajapaksa will swear in his elder brother Mahinda, a former president himself, as prime minister, a spokesman told AFP on Wednesday.  

Government spokesperson Vijayananda Herath said Mahinda Rajapaksa will assume duties as prime minister soon after incumbent Ranil Wickremesinghe steps down on Thursday morning. 

(With input from Xinhua, AFP)