SEOUL (Reuters) - South Korea's extra budget may not be passed by parliament on Tuesday as ruling and opposition lawmakers are at odds over spending details, a senior finance ministry official told Reuters.

Ruling and opposition lawmakers had agreed last week to pass the supplementary budget on Aug. 30, but the main opposition Minjoo Party has been arguing for more spending for young children's education in the plan, which the ruling party is against.

"I don't think it's going to happen today," said the ministry source via phone, who declined to be identified as he was not authorized to speak to media.

One official at the ruling Saenuri Party also told Reuters it looked "difficult" for the extra budget to be ratified on Tuesday, also declining to be identified.

South Korea's finance ministry handed in its extra budget draft for 11.0 trillion won ($9.85 billion) to parliament in late July, which focuses on job creation in the wake of a corporate overhaul of the country's massive shipping and shipbuilding sectors.

($1 = 1,116.6000 won)

(Reporting by Shinhyung Lee; Writing by Christine Kim; Editing by Kim Coghill)