BOSTON – Gov. Deval L. Patrick is scheduled today to sign a $27.4 billion Massachusetts state budget for 2009-2010 that includes deep spending cuts and a hike in the Bay State’s sales tax from 5 percent to 6.25 percent.

The tax-and-spending plan for the 2010 fiscal year, which starts Wednesday, was approved by both houses of the Massachusetts legislature earlier this month. Patrick’s decision to sign the bill follows a months-long standoff between him and lawmakers over ethics and transportation reforms for which the governor finally won approval last week.

“I will approve the new revenues we need to bring our budget into balance, offset the need for even more difficult cuts, and expand opportunity throughout the Commonwealth,” Patrick said in a statement last week. “Due to the economic challenges that all states are facing, this new revenue is necessary to prevent us from losing ground on our long-term goals in education and healthcare, and further straining safety net services that are struggling to meet the increased demand.”

The sales tax increase is the biggest broad-based tax increase in Massachusetts in 20 years, according to The Associated Press. It would take effect on Aug. 1 and bring Massachusetts within three-quarters of a percentage point of Rhode Island’s 7 percent sales tax.

Patrick is expected to sign the budget in his office this afternoon. The Boston Globe reported that Patrick plans to amend and veto portions of the plan. A two-thirds vote by lawmakers would be required to override Patrick’s changes.

Mass. Treasurer Timothy P. Cahill, who is considering challenging Patrick in the Democratic gubernatorial primary next year, has come out against the sales tax increase and said the state should instead pare back the landmark universal health care program it implemented in 2006.