The National Trust, the British Trust for Conservation Volunteers (BTCV), the RSPB, the Youth Hostels Association and The Wildlife Trusts will be launching the scheme on 15 October.
Tony Newby, volunteer support manager at BTCV, said: "The programme will be developing standards in employee volunteering and also promoting it."
The Employee Volunteering Programme will be driven by a web site powered by volunteering site Do-it.org, where companies and employees can access a database of the opportunities available at the five organisations involved.
Helen Toogood, project manager of the Employee Volunteering Programme, said: "Information packs will be sent to companies encouraging them to get involved in employee volunteering."
The programme has an advisory group made up of representatives from the founder organisations, the Active Community Unit and other stakeholders.
It will communicate regularly by teleconference.
"The scheme will create more space for collaboration between the organisations,
said Newby. "Other programmes can overlap and feed into each other."
He added that different parts of the organisations involved had already started meeting more often as a result of the initiative.
Initially, the programme will focus on four main areas of employee volunteering: group or team events lasting for up to several days; placements for between one and 12 months; secondments lasting one to three years; and projects for newly recruited graduates on a day release basis.
The programme was initiated by the National Trust and has received £134,000 from the Active Community Unit to fund it for three years. The money will be used to provide 94 team projects, eight attachments or placements and four secondments by April 2003. It is hoped 960 people will sign up in total.
"We have all been involved in employee volunteering on a more local and ad hoc basis, but this more consolidated approach will allow us to provide better opportunities,
"Employee volunteering has a double benefit. The work gets done and the volunteers all get to know each other a bit better which will improve the working environment.