County councillors have agreed to increase the tax residents pay for services such as road maintenance and social care by 2.99% – but not all members voted in favour of the rise.

Residents living in Band D properties will pay an extra 78p a week to Staffordshire County Council from April after budget plans were passed.

Four Labour members voted against the budget at this month's full council meeting. But Conservative members questioned why an alternative budget was not presented by those opposing the proposals put forward.

Council leader Alan White told the meeting that spending plans for the financial year ahead include £18m on new and expanded school buildings, £1m preparing for the arrival of gigabit broadband, £44m highway investment, £6m to tackle ill health caused by cold homes and £5.4 towards becoming carbon-neutral.

He said: "In the face of all the challenges and uncertainties of recent years, Staffordshire County Council remains a financially stable authority with a balanced budget, able to invest in the long term prosperity of our residents, whilst supporting those in need today and tomorrow. Creating the right conditions for growth and job creation will mean more money in residents' pockets, provide more opportunities for them to lead the lives they want and put less reliance on the public sector so we can target our resources where they are needed most.

"In the next year we will oversee more than £350m of investment in the county, ranging from business development, skills training and town centre regeneration projects in partnership with district and borough colleagues to additional road repairs, school expansion and preparation for the next generation broadband. In the year ahead work is scheduled to begin on the Chatterley Valley West employment site in Newcastle, which will eventually create up to 1,700 jobs.

"Work continues on the Pets at Home national headquarters in Stafford and the i54 South Staffordshire extension, all creating jobs for residents. At the same time we will begin to feel the benefits of the newly-opened £17.4m Lichfield Bypass and the £63m Stafford Western Access Route, as they reduce congestion and open land for 3,500 homes to be built.

"There are also around £40m in public health programmes, which will include treating drug and alcohol addiction, helping hundreds of people lose weight before they contract diabetes, supporting young peoples' mental wellbeing and maintaining people's good health for longer in later life. Our focus remains on encouraging our residents to live independent lives, supported by their communities, wherever possible, which is why we continue to support the voluntary sector and communities' abilities to support themselves."

More than £360m – almost two thirds of the budget – will be spent on social care. The 2.99% council tax rise includes a 1% increase specifically for funding costs of care for vulnerable children and adults.

Councillor White said: "Supporting older people is an essential duty but the reality is that as more of us live for longer, the cost of that support is mounting and it is increasingly difficult for councils to sustain from local taxation.

"The Government's planned increase in National Insurance Levy is intended to support adult social care, but for the time being that money is being used for the NHS and we have to carry on funding it from council tax.

"We also know that plans to cap care spending at £86,000 per person means that more people will be eligible for their care to be funded by the council and there will be higher costs from providers.

"There has to be a long term national solution to social care and a settlement spanning several years would let us plan for the future rather than 12 months at a time."

Opposition group leader Councillor Charlotte Atkins said the Government had failed the authority and Staffordshire residents.

"Staffordshire is one of the most underfunded local authorities in England", she said. "Yet, after waiting years for the Fair Funding Review, it seems no closer to delivery. Even an interim measure proposed by this council and others, to introduce a funding floor for councils like Staffordshire, is just a forlorn hope at the moment.

"The Social Care White Paper does nothing to restore the staffing crisis or the fragility of the care market and puts additional administrative and financial burdens onto the county council. Then, to add insult to injury, our residents are being asked to pay twice for social care; once with the 1% social care levy and secondly with the National Insurance hike.

"With two thirds of the county's budget taken up by social care everything else is squeezed – it's bound to be squeezed. The most visibly obvious is highways. Our roads are plagued with potholes, yet unbelievably the Government has delivered a 25% cut in the highways grant. How does that make sense?

"Our residents are being asked to pay more to get much less. Therefore unfortunately I can't support this budget."