A Church of England bishop has expressed his "very deep concern" about the physical and mental health of his clergy after figures were released showing nine clergy in his diocese were forced to resign on health grounds between 1999 and 2005.

Full figures for 2006 are not yet available, but the Bishop of Lichfield, the Rt Rev Jonathan Gledhill, confirmed that during the year two senior incumbents had died unexpectedly in service - the Rev Martin Leigh, Vicar of Cheddleton and Rural Dean of Leek, and the Rev Victor Evans, Team Rector of the Uttoxeter Area.

In the same year two other incumbents had left their posts several years before retirement in order to take up secular jobs (one has since returned) and two incumbents have had serious heart problems.

The figures, which were released in answer to a question at Lichfield's Diocesan Synod on Saturday also reveal that the number of budgeted full-time stipendiary clergy in the diocese had fallen by 49 from 386 in 2000 to 337 in 2005, a reduction of more than 12.5 per cent.

Most of the cuts had come as part of a planned five-year financial strategy designed to turn the diocesan finances around. That strategy, which concludes at the end of this year, has proved successful and Bishop Gledhill has recently spoken of once again being able to increase clergy numbers.

Bishop Gledhill told the Synod: "We know that, although the clergy consistently score among the highest of all the professions in surveys of job satisfaction, the work feels more demanding and difficult than it did 20 years ago and, even when the entire new lay and non-stipendiary ministry is taken into account, clergy are becoming more episcopal and are more thinly spread than they were.

"We live in a world where volunteers are harder to find and the law has, for good and ill, increased the professionalising of volunteers. There is greater litigiousness and distrust of all authority, including in the Church. The clustering of churches demands new ways of working and increasing use of administrators. Teamwork is the way forward but supporting a team can be demanding."

He said the diocese would be introducing health check-ups for clergy so that any health problems could be caught in good time, adding that all clergy and lay leaders are supported by a network of prayer. Regular and systematic prayer for one another is made possible by the monthly prayer diary which can be kept in one's Bible or prayer book.

"We all have a part to play in our welfare. Every Deanery Chapter is called to be a fellowship of mutual support, where the main item on every agenda is prayer and the study of the Scriptures together."

The figures were released as part of an answer to a question from the Rev Peter Dakin, Priest in Charge of Fulford-in-Stone with Hilderstone and Rural Officer for Staffordshire. He said: "Each year a number of clergy leave the stipendiary ministry prematurely for health reasons, including death in service. This places regrettable burdens on clergy families, parishes, churchwardens and the diocese."

In a supplementary question, the Rev David Baldwin, the vicar of five rural parishes in north Shropshire, Rural Dean of Wem and Whitchurch and Rural Officer for Shropshire, asked Bishop Gledhill to ensure that in addition to physical health, the health-checks also considered mental health. He said that anxiety and stress were significant issues today.

Responding, Bishop Gledhill agreed that this was a "hugely important question" which was being looked at as part of a ministerial review.

He added: "Sometimes we overstrain the clergy and this is something we need to look at."