Ministry is usually referred to as special work, God's work. Ministry is elevated above other work. Ordinary work becomes defined as ministry if it is done within a Christian organisation.
I would argue that these differentiations are problematic. All work is ministry, if it is done with a heart seeking to serve God. The word 'ministry' is from the Latin meaning "serving under authority", and in the Bible it is translated from 'diakonia' a Greek word which means "service among others".
Unfortunately 'ministry' can be used in ways that become detrimental. It can create an artificial barrier between Christians doing ordinary work and Christians doing 'special' or church work.
It can be used to justify neglect of family ("I haven't been home any night this week because I am doing ministry"), or to elevate certain forms of work ("I need to be supported for this ministry"), or to denote a special calling from God ("I sacrificed my job so I could do this ministry").
We tend to only pray in church for people who are doing 'ministry'.
Some people expect their ministry to be supported by others who are doing paid work, merely on the basis that it is 'God's work'.
I have been told by a chaplain that work-life balance did not apply to him because he was doing ministry.
I know people who devalue the work they do because it isn't ministry.
When I ask people what work they do for God, they usually list those things they would define as ministry: evangelism, prayer, Bible study and roles with their local church.
I like a line that Ben Witherington uses in his book Kingdom Work: "work as ministry". I think if workplace Christians thought of their work as ministry, and church workers saw their ministry as work, we might be able to work more effectively together for God's glory.