Congo Republic's ruling Congolese Workers Party (PCT) and allies maintained their grip on the Senate upper house of parliament, winning 29 of 36 seats up for renewal in a mid-term election, results showed on Monday.

President Denis Sassou Nguesso's ruling PCT won 12 seats and the other parties in the alliance won 17 seats in Sunday's vote to renew half the 72-seat house to hold a total 63 seats. Congo staggers election of its senators across their six-year term.

The PCT and its allies also have a large majority in the lower house, meaning they dominate the legislative process.

Nguesso is seeking to diversify the economy away from the oil on which it has been long dependent.

Congo on Saturday announced its 2012 budget would be based on record forecast receipts of 3.646 trillion CFA francs, allowing it to target a budget surplus of close to 17 percent of gross domestic product.