Claims by the Conservatives that a delay in getting a new £30 million computer system fully online shows business incompetence has been dismissed as "electioneering" by leaders of Liberal Democrat-controlled Somerset County Council.

The system, known as SAP, is part of the controversial Southwest One partnership that the county council and other public service organisations entered into with IBM.

It will allow staff across Somerset County Council, Taunton Deane Borough Council, Avon and Somerset police and the Devon and Somerset Fire Brigade to book holidays, track sickness and deliver wages. It will also be used to buy goods and services and record financial transactions.

The county council said the system was designed to save millions of pounds of taxpayers' money.

It had originally been intended that SAP would go live on February 1, but then April 1 was announced as a more realistic date. Although most of the functions will be launched on April 1, the county council now believes the system will not be fully operational until June.

Councillor Ken Maddock, leader of the council's Conservative group, said: "The Lib Dems committed themselves to spending £30m on the SAP system, but it seems as if the delayed launch date of April 1 was just an April Fool. Now they're telling us that the system won't be fully operational until June. You cannot run a business like this."

Fellow Tory councillor David Huxtable said: "When IBM introduced SAP for the DVLA in Swansea, it was supposed to save them £57m but, with delays, ended up costing an extra £81m."

Cllr Harvey Siggs said: "This system would finally have given us a real and accurate number of how many staff the Lib Dems employ at Somerset County Council. However, because of this delay, the Lib Dems won't be able to provide these figures to us until after the election in June. Do they have something to hide from the electorate?"

In a statement, the council said: "The decision to take a phased approach has been made to recognise the complexities of bringing a new system across four separate authorities, and will not bring any additional costs to the taxpayer."

Cllr Sam Crabb, portfolio holder for strategic finance and resources, said: "We are quite happy with the progress. I never expected the whole thing to be up and running in February. That was the initial desire, but we decided to put it back to April 1 pretty soon after. This is quite a major computer upgrade for the county council and it is very complex. The fact that the majority has been put back to April 1 with a slight delay on the small amount left isn't a real problem at all. We have to do it in a sensible way. You must not overload people when making a complex change.

"This is the usual Conservative rubbish. It's electioneering. Harvey Siggs gets an email every month telling him how many staff there are in every single department."