Siniora's trip on Sunday comes a day after his government, the first of the post-Syrian era, won parliamentary approval, drawing a line under a tortuous process that led to the formation of his cabinet.
Relations with Syria have deteriorated since Damascus ended its three-decade military presence in Lebanon in April and anti-Syrian parties won a parliamentary majority in elections in May and June.
Siniora has called for "healthy, privileged and solid relations" with Syria, which had dominated Lebanese life after the 1975-1990 civil war.
He is to meet Syrian President Bashar al-Assad and Prime Minister Muhammad Naji Otri during his visit, Lebanese officials said on Saturday.
"I want to come back with a new way of dealing between Lebanon and Syria, a new thinking, that we should co-operate and create an attitude of openness between the two countries," he said in an interview with the Financial Times published on Thursday.
Syria has blocked Lebanese trucks
at its border in a major trade blow
"The attitude has to be based on mutual interest and respect."
Since the elections, the two sides have been locked in a row, with Lebanese trucks being blocked at the border in a major blow to trade, and large numbers of Syrian workers have left Lebanon, depriving their country of desperately needed remittances.
Siniora, 62, is a former finance minister and close ally of former predecessor Rafiq al-Hariri, killed in a massive bomb blast in Beirut in February widely blamed on Syria and its allies in Lebanon.
In Saturday's confidence vote, lawmakers in the 128-member parliament backed his government by 92 votes to 14 with two abstentions.
Siniora's line-up, which took weeks of talks and stinging political rows to form, is the first elected government since the April Syrian troop pullout in the face of fierce international pressure.
"I want to come back with a new way of dealing between Lebanon and Syria, a new thinking, that we should co-operate and create an attitude of openness between the two countries"
Lebanese prime minister
His cabinet includes a minister from the Hizb Allah movement, which Washington regards as a terrorist organisation.
Siniora presented a series of reforms to parliament on Thursday, pledging a programme to focus on national reconciliation and democracy.
Subsequent parliamentary debate centred on several hot topics such as loosening Syria's clampdown on Lebanese commercial cross-border transit and the future of Hizb Allah which the United Nations has called on to disarm.